Williams Obstetrics, 24th Edition

CHAPTER 27. Vaginal Delivery

ROUTE OF DELIVERY

PREPARATION FOR DELIVERY

OCCIPUT ANTERIOR POSITION

PERSISTENT OCCIPUT POSTERIOR POSITION

OCCIPUT TRANSVERSE POSITION

SHOULDER DYSTOCIA

SPECIAL POPULATIONS

THIRD STAGE OF LABOR

“FOURTH STAGE” OF LABOR

EPISIOTOMY

The natural culmination of second-stage labor is controlled vaginal delivery of a healthy neonate with minimal trauma to the mother. Vaginal delivery is the preferred route of delivery for most fetuses, although certain clinical settings may favor cesarean delivery. Spontaneous vaginal delivery is typical, however, maternal or fetal complications may warrant operative vaginal delivery as described in Chapter 29. Last, a malpresenting fetus or multifetal gestation in many cases may be delivered vaginally but requires special techniques. These are described in Chapters 28—Breech Delivery and 45—Multifetal Pregnancy.

ROUTE OF DELIVERY

In general, spontaneous vaginal vertex delivery poses the lowest risk of most maternal and fetal comorbidity. Compared with cesarean delivery, spontaneous vaginal delivery has lower associated rates of maternal infection, hemorrhage, anesthesia complications, and peripartum hysterectomy, among others. In contrast, for women undergoing spontaneous vaginal delivery compared with cesarean delivery, pelvic floor disorders may be increased (Handa, 2011; Rortveit, 2003). Longitudinal studies, however, suggest that initial pelvic floor protection advantages gained from cesarean delivery are lost as women age (Dolan, 2010; Glazener, 2013; Rortveit, 2001). During their State-of-the-Science Conference, the National Institutes of Health panel (2006) summarized that stress urinary incontinence rates after elective cesarean delivery are lower than those following vaginal delivery. However, the duration of this protection is unclear, particularly in older and multiparous populations. This same conference considered the evidence implicating vaginal delivery in other pelvic floor disorders to be weak and not favoring either delivery route.

PREPARATION FOR DELIVERY

The end of second-stage labor is heralded as the perineum begins to distend, the overlying skin becomes stretched, and the fetal scalp is seen through the separating labia. Increased perineal pressure from the fetal head creates reflexive bearing-down efforts, which are encouraged when appropriate. At this time, preparations are made for delivery. Some considerations that arise during labor and which are also discussed in Chapter 22 (p. 451) are reiterated. For example, the bladder is palpated, and if it is distended, catheterization may be necessary. Continued attention is also given to fetal heart rate monitoring. As one example, a nuchal cord often tightens with descent and may lead to deepening variable decelerations. Antibiotic prophylaxis against infective endocarditis is not recommended for vaginal delivery in most women with cardiac conditions. Exceptions are in women with cyanotic heart disease or prosthetic valves or both. For these women, prophylaxis as outlined in Table 49-10 (p. 991) is indicated 30 to 60 minutes before the anticipated procedure (American College of Obstetricians and Gynecologists, 2011).

During second-stage labor, pushing positions may vary. But for delivery, dorsal lithotomy position is the most widely used and often the most satisfactory. For better exposure, leg holders or stirrups are used. Corton and associates (2012) found no increased rates of perineal lacerations with stirrup use compared to without their use. With positioning, legs are not separated too widely or placed one higher than the other. Within the leg holder, the popliteal region should rest comfortably in the proximal portion and the heel in the distal portion. The legs are not strapped into the stirrups, thereby allowing quick flexion of the thighs backward onto the abdomen should shoulder dystocia develop (p. 541). Legs may cramp during the second stage, in part, because of pressure by the fetal head on pelvic nerves. Cramping may be relieved by repositioning the affected leg or by brief massage.

Preparation for delivery includes vulvar and perineal cleansing. If desired, sterile drapes may be placed in such a way that only the immediate area around the vulva is exposed. In the past, scrubbing, gowning, gloving, and donning protective mask and eyewear was done to protect the laboring woman from infectious agents. Although these considerations remain valid, infectious disease exposure concerns today must also be extended to health-care providers.

OCCIPUT ANTERIOR POSITION

By the time of perineal distention, the position of the presenting occiput is usually known. In some cases, however, molding and caput formation have precluded accurate identification. At this time, careful assessment is again performed as described in Chapter 22 (p. 438). In most cases, presentation is directly occiput anterior or is rotated slightly oblique. But, in perhaps 5 percent, persistent occiput posterior is identified. Rarely, the vertex will be presenting in the occiput transverse position when the head bulges the perineum.

image Delivery of the Head

With each contraction, the vulvovaginal opening is dilated by the fetal head to gradually form an ovoid and finally, an almost circular opening (Fig. 27-1). This encirclement of the largest head diameter by the vulvar ring is termed crowning. Unless an episiotomy has been made as described later, the perineum thins and especially in nulliparous women, may undergo spontaneous laceration. The anus becomes greatly stretched, and the anterior wall of the rectum may be easily seen through it.

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FIGURE 27-1 Delivery of the head. The occiput is being kept close to the symphysis by moderate pressure on the fetal chin at the tip of the maternal coccyx.

There once was considerable controversy concerning routine episiotomy use. It is now clear that episiotomy increases the risk of a tear into the external anal sphincter, the rectum, or both. Conversely, anterior tears involving the urethra and labia are more common in women in whom an episiotomy is avoided. Most, including us, advocate individualization and do not routinely perform episiotomy.

To limit spontaneous vaginal laceration, some perform intrapartum perineal massage to widen the introitus for head passage. With this, the perineum is grasped in the midline by both hands using the thumb and opposing fingers. Outward and lateral stretch against the perineum is then repeatedly applied. Evidence for this technique is limited and mixed regarding efficacy for perineal protection when applied either antepartum or intrapartum (Geranmayeh, 2012; Mei-dan, 2008; Stamp, 2001).

When the head distends the vulva and perineum enough to open the vaginal introitus to a diameter of 5 cm or more, a gloved hand may be used to support the perineum (Fig. 27-2). The other hand is used to guide and control the fetal head to avoid expulsive delivery. Slow delivery of the head may decrease lacerations (Laine, 2008). Alternatively, if expulsive efforts are inadequate or expeditious delivery is needed, the modified Ritgen maneuver may be employed. With this, gloved fingers beneath a draped towel exert forward pressure on the fetal chin through the perineum just in front of the coccyx. Concurrently, the other hand presses superiorly against the occiput (Fig. 27-3). Originally described in 1855, the Ritgen maneuver allows controlled fetal head delivery (Cunningham, 2008). It also favors neck extension so that the head passes through the introitus and over the perineum with its smallest diameters. Comparing the Ritgen maneuver with simple perineal support in 1623 women, Jönsson and colleagues (2008) found a similar incidence of third- and fourth-degree tears—5.5 percent with the maneuver and 4.4 percent with simple support. Last, some espouse a “hands-poised” method, in which the attendant does not touch the perineum during delivery of the head (Mayerhofer, 2002; McCandlish, 1998). Compared with traditional perineal support, this expectant method does not appear to offer greater third-degree laceration protection (Aasheim, 2011).

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FIGURE 27-2 Delivery of the head. The mouth appears over the perineum.

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FIGURE 27-3 Modified Ritgen maneuver. Moderate upward pressure is applied to the fetal chin by the posterior hand covered with a sterile towel, while the suboccipital region of the fetal head is held against the symphysis.

image Delivery of the Shoulders

Following delivery of the fetal head, a finger should be passed across the fetal neck to determine whether it is encircled by one or more umbilical cord loops (Fig. 27-4). A nuchal cord is found in approximately 25 percent of deliveries and ordinarily causes no harm. If an umbilical cord coil is felt, it should be slipped over the head if loose enough. If applied too tightly, the loop should be cut between two clamps. Such tight nuchal cords complicate approximately 6 percent of all deliveries but are not associated with worse neonatal outcome than those without a cord loop (Henry, 2013).

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FIGURE 27-4 The umbilical cord, if identified around the neck, is readily slipped over the head.

Following its delivery, the fetal head falls posteriorly, bringing the face almost into contact with the maternal anus. The occiput promptly turns toward one of the maternal thighs, and the head assumes a transverse position (Fig. 27-5). This external rotation indicates that the bisacromial diameter, which is the transverse diameter of the thorax, has rotated into the anteroposterior diameter of the pelvis.

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FIGURE 27-5 Delivery of the shoulders. A. Gentle downward traction to effect descent of the anterior shoulder. B. Delivery of the anterior shoulder completed. Gentle upward traction to deliver the posterior shoulder.

Most often, the shoulders appear at the vulva just after external rotation and are born spontaneously. If delayed, extraction aids controlled delivery. The sides of the head are grasped with two hands, and gentle downward traction is applied until the anterior shoulder appears under the pubic arch. Next, by an upward movement, the posterior shoulder is delivered. During delivery, abrupt or powerful force is avoided to avert brachial plexus injury.

The rest of the body almost always follows the shoulders without difficulty. With prolonged delay, however, its birth may be hastened by moderate traction on the head and moderate pressure on the uterine fundus. Hooking the fingers in the axillae is avoided. This can injure upper extremity nerves and produce a transient or possibly permanent paralysis. Traction, furthermore, should be exerted only in the direction of the long axis of the neonate. If applied obliquely, it causes neck bending and excessive brachial plexus stretching. Immediately after delivery of the newborn, there is usually a gush of amnionic fluid, often blood-tinged but not grossly bloody.

Previously, immediate nasopharyngeal bulb suctioning of the newborn was routine to remove secretions. It was found, however, that suctioning of the nasopharynx may lead to neonatal bradycardia (Gungor, 2006). The American Heart Association neonatal resuscitation recommendations currently eschew most suctioning immediately following birth—even with meconium present. This includes bulb syringe aspiration. Suctioning should be reserved for neonates who have obvious obstruction to spontaneous breathing or who require positive-pressure ventilation (Kattwinkel, 2010). Similarly, if meconium is present and the newborn is depressed, then intubation and tracheal suctioning is recommended (American College of Obstetricians and Gynecologists, 2013b). These aspects are discussed in further detail in Chapter 33 (p. 638).

image Clamping the Cord

The umbilical cord is cut between two clamps placed 6 to 8 cm from the fetal abdomen, and later an umbilical cord clamp is applied 2 to 3 cm from its insertion into the fetal abdomen. A plastic clamp that is safe, efficient, and fairly inexpensive, such as the Double Grip Umbilical Clamp (Hollister), is used at Parkland Hospital.

For term neonates, the timing of umbilical cord clamping remains debatable. A delay in umbilical cord clamping for up to 60 seconds may increase total body iron stores, expand blood volume, and decrease anemia incidence in the neonate (Andersson, 2011; Yao, 1974). This may be particularly valuable in populations in which iron deficiency is prevalent (Abalos, 2009). Conversely, and as discussed in Chapter 33 (p. 643), higher hemoglobin concentration increases risks for hyperbilirubinemia and extended hospitalization for neonatal phototherapy (McDonald, 2008). Delayed cord clamping may also hinder timely and needed neonatal resuscitation. Fortunately, in general, delayed umbilical cord clamping compared with early clamping does not worsen Apgar scores, umbilical cord pH, or respiratory distress caused by polycythemia. Regarding maternal outcomes, rates of postpartum hemorrhage are similar between early and delayed clamping groups (Andersson, 2013). Fewer data are available regarding cord “milking,” in which the operator pushes blood through the cord toward the newborn. This maneuver appears safe and may be advantageous if rapid cord clamping is clinically indicated (Upadhyay, 2013).

For the preterm neonate, delayed cord clamping has several benefits. These include higher red cell volume, decreased need for blood transfusion, better circulatory stability, and lower rates of intraventricular hemorrhage and of necrotizing enterocolitis (Rabe, 2012; Raju, 2013; Sommers, 2012).

The American College of Obstetricians and Gynecologists (2012c) has concluded that there is insufficient evidence to support or refute benefits from delayed umbilical cord clamping for term neonates in resource-rich settings. For preterm newborns, however, evidence supports delaying umbilical cord clamping to 30 to 60 seconds after birth. This opinion is also endorsed by the American Academy of Pediatrics (2013). Our policy is to clamp the cord after assessing the need to clear the airway, all of which usually requires approximately 30 seconds. The newborn is not elevated above the introitus at vaginal delivery or much above the maternal abdominal wall at the time of cesarean delivery.

PERSISTENT OCCIPUT POSTERIOR POSITION

Approximately 2 to 10 percent of singleton term cephalic fetuses deliver in an occiput posterior (OP) position (Cheng, 2010). As shown in Figure 27-6, many fetuses delivering OP were occiput anterior (OA) in early labor and reflect malrotation during labor. Predisposing risks include epidural analgesia, nulliparity, greater fetal weight, and prior OP position delivery (Cheng, 2006a; Gardberg, 2004; Lieberman, 2005).

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FIGURE 27-6 Occiput posterior (OP) presentation in early labor compared with presentation at delivery. Sonography was used to determine position of the fetal head in early labor. OA = occiput anterior. (Data from Gardberg, 1998.)

image Morbidity

Women with a persistent OP position have higher associated rates of prolonged second-stage labor, cesarean delivery, and operative vaginal delivery. For women who deliver vaginally, rates of blood loss and of third- and fourth-degree laceration, so-called higher-order vaginal lacerations, are increased (Senécal, 2005).

Infants delivered from an OP position have many more complications then those born positioned OA. Cheng and coworkers (2006b) compared outcomes of 2591 women undergoing delivery with a persistent OP position with those of 28,801 women whose newborns were delivered OA. Virtually every possible delivery complication was found more frequently with persistent OP position. Only 46 percent of these women delivered spontaneously, and the remainder accounted for 9 percent of cesarean deliveries performed. These investigators also found that an OP position at delivery was associated with increased adverse short-term neonatal outcomes that included acidemic umbilical cord gases, birth trauma, Apgar scores < 7, and intensive care nursery admission, among others. Similar results were reported by Ponkey (2003) and Fitzpatrick (2001) and their associates.

Methods to prevent persistent OP position and its associated morbidity have been investigated. First, digital examination for identification of fetal head position can be inaccurate, and sonography can be used to increase accuracy (Dupuis, 2005; Souka, 2003; Zahalka, 2005). Such information may provide an explanation for prolonged second-stage labor or may identify suitable candidates for manual rotation. In contrast, varying maternal position either before or during labor does not appear to lower rates of persistent OP position (Desbriere, 2013; Kariminia, 2004).

image Delivery of Persistent Occiput Posterior Position

Delivery of a fetus with an OP position may be completed by spontaneous or operative vaginal delivery. First, if the pelvic outlet is roomy and the vaginal outlet and perineum are somewhat relaxed from prior deliveries, rapid spontaneous OP delivery will often take place. Conversely, if the vaginal outlet is resistant to stretch and the perineum is firm, second-stage labor may be appreciably prolonged. During each expulsive effort, the head is driven against the perineum to a much greater degree than when the head position is OA. This leads to greater rates of higher-order perineal lacerations (Groutz, 2011; Melamed, 2013).

In some cases, spontaneous vaginal delivery from an OP position does not appear feasible or expedited delivery is needed. Here, manual rotation with spontaneous delivery from an OA position may be preferred. This technique is described fully in Chapter 29 (p. 580). Successful rotation rates range from 47 to 90 percent. And, as would be expected, lower rates of cesarean delivery, vaginal laceration, and maternal blood loss follow rotation to OA position and vaginal delivery (Le Ray, 2005; Sen, 2013; Shaffer, 2006, 2011). Disadvantageously, manual rotation is linked with higher cervical laceration rates. Thus, careful inspection of the cervix following rotation is prudent.

For exigent delivery, forceps or vacuum device can be applied to a persistent OP position. This is often performed in conjunction with an episiotomy. Also, if the head is engaged, the cervix fully dilated, and the pelvis adequate, forceps rotation may be attempted. These circumstances most likely prevail when expulsive efforts of the mother during the second stage are ineffective. Both these operative vaginal techniques are detailed in Chapter 29 (p. 582).

Infrequently, protrusion of fetal scalp through the introitus is the consequence of marked elongation of the fetal head from molding combined with formation of a large caput succedaneum. In some cases, the head may not even be engaged—that is, the biparietal diameter may not have passed through the pelvic inlet. In these, labor is characteristically long and descent of the head is slow. Careful palpation above the symphysis may disclose the fetal head to be above the pelvic inlet. Prompt cesarean delivery is appropriate.

At Parkland Hospital, spontaneous delivery or manual rotation is preferred for management of persistent OP position. In other cases, either manual rotation to OA position followed by forceps delivery or forceps delivery from the OP position is used. If neither can be completed with relative ease, cesarean delivery is performed.

OCCIPUT TRANSVERSE POSITION

In the absence of a pelvic architecture abnormality or asynclitism, the occiput transverse position is usually transitory. Thus, unless contractions are hypotonic, the head usually spontaneously rotates to an OA position. If hypotonic uterine contractions are suspected and cephalopelvic disproportion is absent, then an oxytocin infusion can be used to stimulate labor.

If rotation ceases because of poor expulsive forces, vaginal delivery usually can be accomplished readily in a number of ways. The easiest is manual rotation of the occiput either anteriorly to OA or less commonly, posteriorly to OP. If either is successful, Le Ray and coworkers (2007) reported a 4-percent cesarean delivery rate compared with a 60-percent rate in women in whom manual rotation was not successful. Some recommend rotation with Kielland forceps for the persistent occiput transverse position as outlined in Chapter 29 (p. 582). These forceps are used to rotate the occiput to the anterior position, and delivery is accomplished with the same forceps or by substitution with either Simpson or Tucker–McLane forceps.

In some cases, there may be an underlying cause leading to the persistent occiput transverse position that is not easily overcome. For example, a platypelloid pelvis is flattened anteroposteriorly and an android pelvis is heart shaped. With these, there may be inadequate space for occipital rotation to either an OA or OP position (Fig. 2-20p. 34). Because of these concerns, undue force should be avoided if forceps delivery is attempted.

SHOULDER DYSTOCIA

Following complete emergence of the fetal head during vaginal delivery, the remainder of the body may not rapidly follow. The anterior fetal shoulder can become wedged behind the symphysis pubis and fail to deliver using normally exerted downward traction and maternal pushing. Because the umbilical cord is compressed within the birth canal, such dystocia is an emergency. Several maneuvers, in addition to downward traction on the fetal head, may be performed to free the shoulder. This requires a team approach, in which effective communication and leadership are critical.

Consensus regarding a specific definition of shoulder dystocia is lacking. Some investigators focus on whether maneuvers to free the shoulder are needed, whereas others use the head-to-body delivery time interval as defining (Beall, 1998). Spong and coworkers (1995) reported that the mean head-to-body delivery time in normal births was 24 seconds compared with 79 seconds in those with shoulder dystocia. These investigators proposed that a head-to-body delivery time > 60 seconds be used to define shoulder dystocia. Currently, however, the diagnosis continues to rely on the clinical perception that the normal downward traction needed for fetal shoulder delivery is ineffective.

Because of these differing definitions, the incidence of shoulder dystocia varies. Current reports cite an incidence between 0.6 percent and 1.4 percent (American College of Obstetricians and Gynecologists, 2012b). There is evidence that the incidence has increased in recent decades, likely due to increasing fetal birthweight (MacKenzie, 2007). Alternatively, this increase may be due to more attention given to appropriate documentation of dystocia (Nocon, 1993).

image Maternal and Neonatal Consequences

In general, shoulder dystocia poses greater risk to the fetus than the mother. Postpartum hemorrhage, usually from uterine atony but also from vaginal lacerations, is the main maternal risk (Jangö, 2012; Rahman, 2009). In contrast, significant neonatal neuromusculoskeletal injury and even mortality are concerns. MacKenzie and associates (2007) reviewed 514 cases of shoulder dystocia and found that 11 percent were associated with serious neonatal trauma. Brachial plexus injury was diagnosed in 8 percent, and 2 percent suffered a clavicle, humeral, or rib fracture. Seven percent showed evidence of acidosis at delivery, and 1.5 percent required cardiac resuscitation or developed hypoxic ischemic encephalopathy. Mehta and colleagues (2007) found a similar number of injuries in a study of 205 shoulder dystocia cases, in which 17 percent had injury. Again, most involved the brachial plexus. These specific injuries are described more fully in Chapter 33 (p. 648). Of predictors, increasing fetal weight, maternal body mass index, and second-stage duration and a prior shoulder dystocia appear to raise the neonatal injury risk with shoulder dystocia (Bingham, 2010; Mehta, 2006).

image Prediction and Prevention

There has been considerable evolution in obstetrical thinking regarding the preventability of shoulder dystocia. Although there are clearly several risk factors associated with this complication, identification of individual instances before the fact has proved to be impossible. The American College of Obstetricians and Gynecologists (2012b) reviewed studies and concluded that:

1. Most cases of shoulder dystocia cannot be accurately predicted or prevented.

2. Elective induction of labor or elective cesarean delivery for all women suspected of having a macrosomic fetus is not appropriate.

3. Planned cesarean delivery may be considered for the nondiabetic woman with a fetus whose estimated fetal weight is > 5000 g or for the diabetic woman whose fetus is estimated to weigh > 4500 g.

Birthweight

Commonly cited maternal characteristics associated with increased fetal birthweight are obesity, postterm pregnancy, multiparity, diabetes, and gestational diabetes. There is universal agreement that increasing birthweight is associated with an increasing incidence of shoulder dystocia. In one study of nearly 2 million vaginal deliveries, Overland and coworkers (2012) noted that in 75 percent of shoulder dystocia cases, newborns weighed > 4000 g. That said, the concept that cesarean delivery is indicated for large fetuses, even those estimated to weigh 4500 g, should be tempered. Rouse and Owen (1999) concluded that a prophylactic cesarean delivery policy for macrosomic fetuses would require more than 1000 cesarean deliveries with attendant morbidity as well as millions of dollars to avert a single permanent brachial plexus injury.

Intrapartum Factors

Some labor characteristics have been associated with an increased shoulder dystocia risk and include prolonged second-stage labor, operative vaginal delivery, and prior shoulder dystocia (Mehta, 2004; Moragianni, 2012; Overland, 2009). Of these, the risk of recurrent shoulder dystocia ranges from 1 to 13 percent (Bingham, 2010; Moore, 2008; Ouzounian, 2013). For many women with prior shoulder dystocia, a trial of labor may be reasonable. The American College of Obstetricians and Gynecologists (2012b) recommends that estimated fetal weight, gestational age, maternal glucose intolerance, and severity of prior neonatal injury be evaluated and risks and benefits of cesarean delivery discussed with any woman with a history of shoulder dystocia. After discussion, either mode of delivery is appropriate.

image Management

Because shoulder dystocia cannot be accurately predicted, clinicians should be well versed in its management principles. Because of ongoing cord compression with this dystocia, one goal is to reduce the head-to-body delivery time. This is balanced against the second goal, which is avoidance of fetal and maternal injury from aggressive manipulations. Accordingly, an initial gentle attempt at traction, assisted by maternal expulsive efforts, is recommended. Adequate analgesia is certainly ideal. Some clinicians advocate performing a large episiotomy to provide room for manipulations. Of note, Paris (2011) and Gurewitsch (2004) and their colleagues reported no change in the brachial plexus injury rate for groups in which episiotomy was not performed during shoulder dystocia management.

After gentle traction, various techniques can be used to free the anterior shoulder from its impacted position behind the symphysis pubis. Of these, moderate suprapubic pressure can be applied by an assistant, while downward traction is applied to the fetal head. Pressure is applied with the heel of the hand to the anterior shoulder wedged above and behind the symphysis. The anterior shoulder is thus either depressed or rotated, or both, so the shoulders occupy the oblique plane of the pelvis and the anterior shoulder can be freed.

The McRoberts maneuver was described by Gonik and associates (1983) and named for William A. McRoberts, Jr., who popularized its use at the University of Texas at Houston. The maneuver consists of removing the legs from the stirrups and sharply flexing them up onto the abdomen (Fig. 27-7). Gherman and associates (2000) analyzed the McRoberts maneuver using x-ray pelvimetry. They found that the procedure caused straightening of the sacrum relative to the lumbar vertebrae, rotation of the symphysis pubis toward the maternal head, and a decrease in the angle of pelvic inclination. Although this does not increase pelvic dimensions, pelvic rotation cephalad tends to free the impacted anterior shoulder. Gonik and coworkers (1989) tested the McRoberts position objectively with laboratory models and found that the maneuver reduced the forces needed to free the fetal shoulder.

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FIGURE 27-7 The McRoberts maneuver. The maneuver consists of removing the legs from the stirrups and sharply flexing the thighs up onto the abdomen. The assistant is also providing suprapubic pressure simultaneously (arrow).

Another maneuver, delivery of the posterior shoulder, consists of carefully sweeping the posterior arm of the fetus across its chest, followed by delivery of the arm. The shoulder girdle is then rotated into one of the oblique diameters of the pelvis with subsequent delivery of the anterior shoulder (Fig. 27-8).

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FIGURE 27-8 Delivery of the posterior shoulder for relief of shoulder dystocia. A. The operator’s hand is introduced into the vagina along the fetal posterior humerus. B. The arm is splinted and swept across the chest, keeping the arm flexed at the elbow. C. The fetal hand is grasped and the arm extended along the side of the face. The posterior arm is delivered from the vagina.

Woods (1943) reported that by progressively rotating the posterior shoulder 180 degrees in a corkscrew fashion, the impacted anterior shoulder could be released. This is frequently referred to as the Woods corkscrew maneuver(Fig. 27-9). Rubin (1964) recommended two maneuvers. First, the fetal shoulders are rocked from side to side by applying force to the maternal abdomen. If this is not successful, the pelvic hand reaches the most easily accessible fetal shoulder, which is then pushed toward the anterior surface of the chest. This maneuver most often abducts both shoulders, which in turn produces a smaller shoulder-to-shoulder diameter. This permits displacement of the anterior shoulder from behind the symphysis (Fig. 27-10).

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FIGURE 27-9 Woods maneuver. The hand is placed behind the posterior shoulder of the fetus. The shoulder is then rotated progressively 180 degrees in a corkscrew manner so that the impacted anterior shoulder is released.

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FIGURE 27-10 The second Rubin maneuver. A. The shoulder-to-shoulder diameter is aligned vertically. B. The more easily accessible fetal shoulder (the anterior is shown here) is pushed toward the anterior chest wall of the fetus (arrow). Most often, this results in abduction of both shoulders, which reduces the shoulder-to-shoulder diameter and frees the impacted anterior shoulder.

Importantly, progression from one maneuver to the next should be organized and methodical. As noted, the urgency to relieve the dystocia should be balanced against potentially injurious traction forces and manipulations. Lerner and coworkers (2011) in their evaluation of 127 shoulder dystocia cases reported that all neonates without sequelae from shoulder dystocia were born by 4 minutes. Conversely, most depressed neonates—57 percent—had head-to-body delivery intervals > 4 minutes. The percentage of depressed neonates rose sharply after 3 minutes.

Deliberate fracture of the anterior clavicle by using the thumb to press it toward and against the pubic ramus can be attempted to free the shoulder impaction. In practice, however, deliberate fracture of a large neonate clavicle is difficult. If successful, the fracture will heal rapidly and is usually trivial compared with brachial nerve injury, asphyxia, or death.

Hibbard (1982) recommended that pressure be applied to the fetal jaw and neck in the direction of the maternal rectum, with strong fundal pressure applied by an assistant as the anterior shoulder is freed. Strong fundal pressure, however, applied at the wrong time may result in even further impaction of the anterior shoulder. Gross and associates (1987) reported that fundal pressure in the absence of other maneuvers “resulted in a 77-percent complication rate and was strongly associated with (fetal) orthopedic and neurologic damage.”

Sandberg (1985) reported the Zavanelli maneuver for cephalic replacement into the pelvis followed by cesarean delivery. The first part of the maneuver consists of returning the head to the occiput anterior or posterior position. Terbutaline, 0.25 mg, is given subcutaneously to produce uterine relaxation. The operator flexes the head and slowly pushes it back into the vagina. Cesarean delivery is then performed. Sandberg (1999) reviewed 103 reported cases in which the Zavanelli maneuver was used. It was successful in 91 percent of cephalic cases and in all cases of breech head entrapments. Despite successful replacement, fetal injuries were common but may have resulted from the multiple manipulations used before the Zavanelli maneuver (Sandberg, 2007). Six stillbirths, eight neonatal deaths, and 10 neonates who suffered brain damage were described. Uterine rupture also was reported.

Symphysiotomy, in which the intervening symphyseal cartilage and much of its ligamentous support is cut to widen the symphysis pubis, is described in Chapter 28 (p. 567). It has been used successfully for shoulder dystocia (Hartfield, 1986). Goodwin and colleagues (1997) reported three cases in which symphysiotomy was performed after the Zavanelli maneuver had failed. All three neonates died, and maternal morbidity was significant due to urinary tract injury. Cleidotomy consists of cutting the clavicle with scissors or other sharp instruments and is usually done for a dead fetus (Schramm, 1983).

Hernandez and Wendel (1990) suggested use of a shoulder dystocia drill to better organize emergency management:

1. Call for help—mobilize assistants and anesthesia and pediatric personnel. Initially, a gentle attempt at traction is made. Drain the bladder if it is distended.

2. A generous episiotomy may be desired to afford room posteriorly.

3. Suprapubic pressure is used initially by most practitioners because it has the advantage of simplicity. Only one assistant is needed to provide suprapubic pressure, while normal downward traction is applied to the fetal head.

4. The McRoberts maneuver requires two assistants. Each assistant grasps a leg and sharply flexes the maternal thigh against the abdomen.

These maneuvers will resolve most cases of shoulder dystocia.

If the above listed steps fail, the following steps may be attempted, and any of the maneuvers may be repeated:

5. Delivery of the posterior arm is attempted. With a fully extended arm, however, this is usually difficult to accomplish.

6. Woods screw maneuver is applied.

7. Rubin maneuver is attempted.

Other techniques generally should be reserved for cases in which all other maneuvers have failed. These include intentional fracture of the anterior clavicle and the Zavanelli maneuver. The American College of Obstetricians and Gynecologists (2012b) has concluded that no one maneuver is superior to another in releasing an impacted shoulder or reducing the chance of injury. Performance of the McRoberts maneuver, however, was deemed a reasonable initial approach. The College (2012a) also has created a Patient Safety Checklist to guide the documentation process with shoulder dystocia.

Shoulder dystocia training and protocols using simulation-based education and drills has evidence-based support. These tools improve performance and retention of drill steps (Buerkle, 2012; Crofts, 2008; Grobman, 2011). Their use has translated into improved neonatal outcome in some, but not all, investigations (Draycott, 2008; Inglis, 2011; Walsh, 2011).

SPECIAL POPULATIONS

Typical vaginal delivery may be challenging in women with perineal limitations or with a large anomalous fetus. Delivery in women with prior pelvic reconstructive surgeries and in those with scarring from female genital mutilation is described here. The special needs of women with congenital vaginal septa, giant condyloma, Crohn disease, or connective-tissue disorders are discussed in chapters covering those topics.

image Female Genital Mutilation

Inaccurately called female circumcision, mutilation refers to medically unnecessary vulvar and perineal modification. In the United States it is a federal crime to perform unnecessary genital surgery on a girl younger than 18 years. That said, forms of female genital mutilation are practiced in countries throughout Africa, the Middle East, and Asia. As many as 130 million women worldwide have undergone one of these procedures, and approximately 230,000 live in the United States (Nour, 2006). Cultural sensitivity is imperative, because many women may be offended by the suggestion that they have been assaulted or mutilated (American College of Obstetricians and Gynecologists, 2007).

The World Health Organization (1997) classifies genital mutilations into four types (Table 27-1). Complications include infertility, dysmenorrhea, diminished sexual quality of life, and propensity for vulvovaginal infection (Almroth, 2005; Andersson, 2012; Nour, 2006). In general, women with significant symptoms following type III procedures are candidates for corrective surgery. Specifically, division of midline scar tissue to reopen the vulva is termed defibulation or deinfibulation.

TABLE 27-1. World Health Organization Classification of Female Genital Mutilation

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Female genital mutilation has been associated with some adverse maternal and neonatal complications. The World Health Organization (2006) estimated that these procedures increased perinatal morbidity rates by 10 to 20 per 1000. Small increased risks for prolonged labor, cesarean delivery, postpartum hemorrhage, and early neonatal death are found by some but not all (Chibber, 2011; Rouzi, 2012; Wuest, 2009). Importantly, the psychiatric consequences can be profound.

For those women who do not desire defibulation until they become pregnant, the procedure can be done at midpregnancy using spinal analgesia (Nour, 2006). Or, as shown in Figure 27-11, another option is to wait until delivery. In women not undergoing defibulation, anal sphincter tear rates with vaginal delivery may be increased (Berggren, 2013; Wuest, 2009). In our experiences, intrapartum defibulation in many cases allows successful vaginal delivery without major complications.

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FIGURE 27-11 Process of defibulation. Although not shown here, lidocaine is first infiltrated along the planned incision. As protection, two fingers of one hand are insinuated behind the shelf created by fused labia but in front of the urethra and crowning head. The shelf is then incised in the midline. After delivery, the raw edges are sutured with rapidly absorbable material to secure hemostasis. (From Rouzi, 2012, with permission.)

image Prior Pelvic Reconstructive Surgery

These surgeries are performed with increasing frequency in reproductive-aged women, and thus pregnancy following these procedures is not uncommon. Logically, there are concerns for symptom recurrence following vaginal delivery, and high-quality data to aid evidenced-based decisions are limited. For women with prior stress urinary incontinence surgery, slightly greater protection against postpartum incontinence is gained by elective cesarean delivery (Pollard, 2012; Pradhan, 2013). Stated another way, most women with prior anti-incontinence surgery can be delivered vaginally without symptom recurrence. Also, cesarean delivery is not always protective. Obviously, symptom recurrence and the need for additional vaginal surgery should be weighed against the surgical risk of cesarean delivery (Groenen, 2008). In those with prior surgeries for anal incontinence or pelvic organ prolapse, only scant information regarding outcomes is available. Such cases require individualization.

image Anomalous Fetuses

Rarely, delivery can be obstructed by extreme macrocephaly secondary to hydrocephaly or by massive fetal abdomen enlargement from a greatly distended bladder, ascites, or large kidneys or liver. With milder forms of hydrocephaly, if the biparietal diameter is < 10 cm or if the head circumference is < 36 cm, then vaginal delivery may be permitted (Anteby, 2003).

In rare cases in which neonatal death has occurred or is certain due to associated anomalies, vaginal delivery may be reasonable, but the head or abdomen must be reduced in size for delivery. Removal of fluid by cephalocentesis or paracentesis with sonographic guidance can be performed intrapartum. For hydrocephalic fetuses that are breech, cephalocentesis can be accomplished suprapubically when the aftercoming head enters the pelvis. For those that require cesarean delivery, fluid removal before hysterotomy circumvents extending a low transverse or lengthening a vertical incision.

THIRD STAGE OF LABOR

image Delivery of the Placenta

Third-stage labor begins immediately after fetal birth and ends with placental delivery. Goals include delivery of an intact placenta and avoidance of uterine inversion or postpartum hemorrhage. The latter two are grave intrapartum complications and constitute emergencies, as described in Chapter 41 (p. 783).

Immediately after newborn birth, uterine fundal size and consistency are examined. If the uterus remains firm and there is no unusual bleeding, watchful waiting until the placenta separates is the usual practice. Massage is not employed, but the fundus is frequently palpated to ensure that it does not become atonic and filled with blood from placental separation. To prevent uterine inversion, umbilical cord traction must not be used to pull the placenta from the uterus. Moreover, placental expression is not forced before placental separation. Signs of separation include a sudden gush of blood into the vagina, a globular and firmer fundus, a lengthening of the umbilical cord as the placenta descends into the vagina, and a rise of the uterus into the abdomen. With the last, the placenta, having separated, passes down into the lower uterine segment and vagina. Here, its bulk pushes the uterus upward.

These signs sometimes appear within 1 minute after newborn delivery and usually within 5 minutes. Once the placenta has detached from the uterine wall, it should be determined that the uterus is firmly contracted. The mother may be asked to bear down, and the intraabdominal pressure often expels the placenta into the vagina. These efforts may fail or may not be possible because of analgesia. After ensuring that the uterus is contracted firmly, pressure is exerted by a hand wrapped around the fundus to propel the detached placenta into the vagina (Fig. 27-12). The umbilical cord is kept slightly taut but is not pulled. Concurrently, the heel of the hand exerts downward pressure between the symphysis pubis and the uterine fundus. This also aids inversion prevention. Once the placenta passes through the introitus, pressure on the uterus is relieved. The placenta is then gently lifted away (Fig. 27-13). Care is taken to prevent placental membranes from being torn off and left behind. If the membranes begin to tear, they are grasped with a clamp and removed by gentle teasing (Fig. 27-14).

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FIGURE 27-12 Expression of placenta. Note that the hand is not trying to push the fundus of the uterus through the birth canal! As the placenta leaves the uterus and enters the vagina, the uterus is elevated by the hand on the abdomen while the cord is held in position. The mother can aid in the delivery of the placenta by bearing down. As the placenta reaches the perineum, the cord is lifted, which in turn lifts the placenta out of the vagina.

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FIGURE 27-13 The placenta is removed from the vagina by lifting the cord.

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FIGURE 27-14 Membranes that were somewhat adhered to the uterine lining are separated by gentle traction with a ring forceps.

image Manual Removal of Placenta

Occasionally, the placenta will not separate promptly. This is especially common with preterm delivery (Dombrowski, 1995). If there is brisk bleeding and the placenta cannot be delivered by the above technique, manual removal of the placenta is indicated, using the safeguards described in Chapter 41 (p. 784). It is unclear how much time should elapse in the absence of bleeding before the placenta is manually removed (Deneux-Tharaux, 2009). If labor analgesia is still intact, some obstetricians practice routine manual removal of any placenta that has not separated spontaneously by the time they have completed delivery of the newborn and care of the cord. The benefits of this practice, however, have not been proven, and most obstetricians await spontaneous placental detachment unless bleeding is excessive. When manual removal is performed, some administer a single dose of intravenous antibiotics similar to that used for cesarean infection prophylaxis (Chap. 30p. 590). The American College of Obstetricians and Gynecologists (2011) has concluded that there are no data to either support or refute this practice.

image Management of the Third Stage

Practices within the third stage of labor may be broadly considered as either physiological or active management. Physiological or expectant management involves waiting for placental separation signs and allowing the placenta to deliver either spontaneously or aided by nipple stimulation or gravity (World Health Organization, 2012). In contrast, active management of third-stage labor consists of early cord clamping, controlled cord traction during placental delivery, and immediate administration of prophylactic uterotonics. The goal of this triad is to limit postpartum hemorrhage (Begley, 2011; Jangsten, 2011; Prendiville, 1988). In addition, uterine massage following placental delivery is recommended by many but not all to prevent postpartum hemorrhage. We support this with the caveat that evidence for this practice is not strong (Abdel-Aleem, 2010). As noted earlier (p. 539), immediate cord clamping does not increase postpartum hemorrhage rates and thus is a less important component of this trio. Similarly, cord traction may also be less critical (Gülmezoglu, 2012).

Therefore, uterotonics appear to be the most important factor to decrease postpartum blood loss. Choices include oxytocin (Pitocin), misoprostol (Cytotec), carboprost (Hemabate), and the ergots, namely ergonovine (Ergotrate) and methylergonovine (Methergine). In addition, a combination agent of oxytocin and ergonovine (Syntometrine) is used outside the United States. Also in other countries, carbetocin (Duratocin), a long-acting oxytocin analogue, is available and effective for hemorrhage prevention during cesarean delivery (Attilakos, 2010; Su, 2012). Of these, the World Health Organization (2012) recommends oxytocin as a first-line agent. Ergot-based drugs and misoprostol are alternatives in settings that lack oxytocin.

Uterotonics may be given before or after placental expulsion without increasing rates of postpartum hemorrhage, placental retention, or third-stage labor length (Soltani, 2010). If they are given before delivery of the placenta, however, they may entrap an undiagnosed, undelivered second twin. Thus, abdominal palpation should confirm no additional fetuses.

High-Dose Oxytocin

Synthetic oxytocin is identical to that produced by the posterior pituitary. Its action is noted at approximately 1 minute, and it has a mean half-life of 3 to 5 minutes. When given as a bolus, oxytocin can cause profound hypotension. Secher and coworkers (1978) reported that an intravenous bolus of 10 units of oxytocin caused a marked transient fall in blood pressure with an abrupt increase in cardiac output. Svanström and associates (2008) confirmed those findings in 10 healthy women following cesarean delivery. Mean pulse rate increased 28 bpm, mean arterial pressure decreased 33 mm Hg, and electrocardiogram changes of myocardial ischemia as well as chest pain and subjective discomfort were noted. These hemodynamic changes could be dangerous for women hypovolemic from hemorrhage or those with cardiac disease. Thus, oxytocin should not be given intravenously as a large bolus. Rather, it should be given as a dilute solution by continuous intravenous infusion or as an intramuscular injection.

Water intoxication can result from the antidiuretic action of high-dose oxytocin if administered in a large volume of electrolyte-free dextrose solution (Whalley, 1963). In a case report, Schwartz and Jones (1978) described convulsions in both a mother and her newborn following administration of 6.5 liters of 5-percent dextrose solution and 36 units of oxytocin before delivery. The cord plasma sodium concentration was 114 mEq/L. Accordingly, if oxytocin is to be administered in high doses for a considerable period of time, its concentration should be increased rather than increasing the infusion flow rate (Chap. 26p. 530).

Despite the routine use of oxytocin, no standard prophylactic dose has been established for its use following either vaginal or cesarean delivery. In an analysis of studies that compared oxytocin dosage, investigators found higher infusion doses to be more effective than lower doses or protracted fixed-dose administration (Roach, 2013; Tita, 2012). Our standard practice, if an intravenous infusion is established, is to add 20 units (2 mL) of oxytocin per liter of infusate. This solution is administered after delivery of the placenta at a rate of 10 to 20 mL/min (200 to 400 mU/min) for a few minutes until the uterus remains firmly contracted and bleeding is controlled. The infusion rate then is reduced to 1 to 2 mL/min until the mother is ready for transfer from the recovery suite to the postpartum unit. The infusion is usually then discontinued. For women without intravenous access, 10 units of intramuscular oxytocin are provided.

Ergonovine and Methylergonovine

These ergot alkaloids have similar activity levels in myometrium, and only methylergonovine is currently manufactured in the United States. These agents require very specific storage conditions, as they deteriorate rapidly with exposure to light, heat, and humidity.

Whether given intramuscularly or orally, both are powerful stimulants of myometrial contraction, exerting an effect that may persist for hours. In pregnant women, an intramuscular or oral dose of 0.2 mg results in tetanic uterine contractions. Effects develop within a few minutes after intramuscular or oral administration. Moreover, the response is sustained with little tendency toward relaxation. Ergots are dangerous for the fetus and mother when given before delivery. Moreover, cases of serious injury and death have been reported when methylergonovine was administered accidentally to newborns in the labor and delivery room instead of vitamin K, hepatitis B vaccine, or naloxone (Aeby, 2003; American Regent, 2012a; Bangh, 2005). The Food and Drug Administration (2012) has added a warning to the package insert recommending a 12-hour delay between the last methylergonovine dose and breast feeding. Despite this, no adverse effects attributable to this drug in breast milk have been reported (Briggs, 2011).

In addition to neonatal concerns, parenteral administration of ergot alkaloids, especially by the intravenous route, may induce transient maternal hypertension. Other reported side effects include nausea, vomiting, tinnitus, headache, and painful uterine contractions. Hypertension is more likely to be severe in women with gestational hypertension. These drugs are contraindicated in patients with hypertension, cardiac disease or occlusive vascular disorders, severe hepatic or renal disease, and sepsis (Novartis, 2012; Sanders-Bush, 2011). Moreover, this drug is not routinely given intravenously to avoid inducing sudden hypertensive and cerebrovascular accidents. If considered a lifesaving measure, however, intravenous methylergonovine should be given slowly during no less than 60 seconds with careful monitoring of blood pressure (American Reagent, 2012b).

Ergot alkaloid agents do not provide superior protection against postpartum hemorrhage compared with oxytocin. Moreover, safety and tolerability are greater with oxytocin (Liabsuetrakul, 2007). For these reasons, ergot alkaloid agents are considered second-line for third-stage labor prevention of hemorrhage.

Misoprostol

This prostaglandin E1 analogue has proved inferior to oxytocin for postpartum hemorrhage prevention (Tunçalp, 2012). Although oxytocin is preferred, in resource-poor settings that lack oxytocin, misoprostol is suitable for hemorrhage prophylaxis and is given as a single oral 600-μg dose (Mobeen, 2011; World Health Organization, 2012). Side effects include shivering in 30 percent and fever in 5 percent. Unlike some other prostaglandins, nausea or diarrhea is infrequent (Derman, 2006; Lumbiganon, 1999; Walraven, 2005).

“FOURTH STAGE” OF LABOR

The hour immediately following delivery of the placenta is critical, and it has been designated by some as the fourth stage of labor. During this time, lacerations are repaired. Although uterotonics are administered, postpartum hemorrhage as the result of uterine atony is most likely at this time. Hematomas may expand. Consequently, uterine tone and the perineum should be frequently evaluated. The American Academy of Pediatrics and the American College of Obstetricians and Gynecologists (2012) recommend that maternal blood pressure and pulse be recorded immediately after delivery and every 15 minutes for the first 2 hours. The placenta, membranes, and umbilical cord should be examined for completeness and for anomalies, as described in Chapter 6 (p. 117).

image Birth Canal Lacerations

Lower genital tract lacerations may involve the cervix, vagina, or perineum. Those of the cervix and vagina are described in Chapter 41 (p. 788). Perineal tears may follow any vaginal delivery and are classified by their depth. Complete definitions and visual examples are given in Figure 27-15. As noted, third- and fourth-degree lacerations are considered higher-order lacerations. Short-term, these are associated with greater blood loss, puerperal pain, and wound disruption or infection risk. Long-term, they are linked with higher rates of anal incontinence and dyspareunia. The incidence of higher-order lacerations varies from 0.25 to 6 percent (Garrett, 2014; Groutz, 2011; Melamed, 2013; Stock, 2013). Risk factors for these more complex lacerations include midline episiotomy, nulliparity, longer second-stage labor, precipitous delivery, persistent occiput posterior position, operative vaginal delivery, Asian race, and increasing fetal birthweight (Landy, 2011; Melamed, 2013). Epidural analgesia was found to be protective (Jango, 2014).

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FIGURE 27-15 Classification of perineal lacerations. A. First-degree lacerations involve the fourchette, perineal skin, and vaginal mucous membrane but not the underlying fascia and muscle. These included periurethral lacerations, which may bleed profusely. B. Second-degree lacerations involve, in addition, the fascia and muscles of the perineal body but not the anal sphincter. These tears may be midline, but often extend upward on one or both sides of the vagina, forming an irregular triangle. C. Third-degree lacerations extend farther to involve the external anal sphincter. D. Fourth-degree lacerations extend completely through the rectal mucosa to expose its lumen and thus involves disruption of both the external and internal anal sphincters. (Used with permission from Drs. Shayzreen Roshanravan and Marlene Corton.)

Morbidity rates rise as laceration severity increases. Stock and coworkers (2013) reported that approximately 7 percent of 909 higher-order lacerations had complications. Williams and Chames (2006) found that mediolateral episiotomy was the most powerful predictor of wound disruption. Goldaber and associates (1993) found that 21 of 390 or 5.4 percent of women with fourth-degree lacerations experienced significant morbidity. There were 1.8 percent dehiscences, 2.8 percent infections plus a dehiscence, and 0.8 percent with isolated infections.

The repair of perineal lacerations is virtually the same as that of episiotomy incisions, albeit sometimes less satisfactory because of tear irregularities. Thus, laceration repair technique is discussed with episiotomy repair.

image Episiotomy

The word episiotomy derives from the Greek episton—pubic region—plus –tomy—to cut. In a strict sense, episiotomy is incision of the pudendum—the external genital organs. Perineotomy is incision of the perineum. In common parlance, however, the term episiotomy often is used synonymously with perineotomy, a practice that we follow here. The incision may be made in the midline, creating a median or midline episiotomy (Fig. 27-16). It may also begin off the midline and directed laterally and downward away from the rectum, termed a mediolateral episiotomy.

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FIGURE 27-16 Midline episiotomy. Two fingers are insinuated between the perineum and fetal head, and the episiotomy is then cut vertically downward.

Episiotomy Indications and Consequences

Although episiotomy is still a common obstetrical procedure, its use has decreased remarkably over the past 30 years. Oliphant and coworkers (2010) used the National Hospital Discharge Survey to analyze episiotomy rates between 1979 and 2006 in the United States. They noted a 75-percent decline in the episiotomy age-adjusted rate. Through the 1970s, however, it was common practice to cut an episiotomy for almost all women having their first delivery. The reasons for its popularity included substitution of a straight surgical incision, which was easier to repair, for the ragged laceration that otherwise might result. The long-held beliefs that postoperative pain is less and healing improved with an episiotomy compared with a tear, however, appeared to be incorrect (Larsson, 1991).

Another commonly cited but unproven benefit of routine episiotomy was that it prevented pelvic floor disorders. A number of observational studies and randomized trials, however, showed that routine episiotomy is associated with an increased incidence of anal sphincter and rectal tears (Angioli, 2000; Nager, 2001; Rodriguez, 2008).

Carroli and Mignini (2009) reviewed the Cochrane Pregnancy and Childbirth Group trials registry. There were lower rates of posterior perineal trauma, surgical repair, and healing complications in women managed with a restrictive use of episiotomy. Alternatively, the incidence of anterior perineal trauma was lower in the group managed with routine use of episiotomy.

With these findings came the realization that episiotomy did not protect the perineal body but contributed to anal sphincter incontinence by increasing the risk of higher-order lacerations. Signorello and associates (2000) reported that fecal and flatal incontinence was increased four- to sixfold in women with an episiotomy compared with a group of women delivered with an intact perineum. Even compared with spontaneous lacerations, episiotomy tripled the risk of fecal incontinence and doubled it for flatal incontinence. Episiotomy without extension did not lower this risk. Despite repair of a third-degree extension, 30 to 40 percent of women have long-term anal incontinence (Gjessing, 1998; Poen, 1998). Finally, Alperin and associates (2008) reported that episiotomy performed for the first delivery conferred a fivefold risk for second-degree or higher-order laceration with the second delivery.

The American College of Obstetricians and Gynecologists (2013a) has concluded that restricted use of episiotomy is preferred to routine use. We are of the view that the procedure should be applied selectively for appropriate indications. Thus, episiotomy should be considered for indications such as shoulder dystocia, breech delivery, macrosomic fetuses, operative vaginal deliveries, persistent occiput posterior positions, and other instances in which failure to perform an episiotomy will result in significant perineal rupture. The final rule is that there is no substitute for surgical judgment and common sense.

Episiotomy Type and Timing

Before episiotomy, analgesia may be provided by existing labor epidural analgesia, by bilateral pudendal nerve blockade, or by infiltration of 1-percent lidocaine. If performed unnecessarily early, bleeding from the episiotomy may be considerable during the interval between incision and delivery. If it is performed too late, lacerations will not be prevented. Typically, episiotomy is completed when the head is visible during a contraction to a diameter of approximately 4 cm, that is, crowning. When used in conjunction with forceps delivery, most perform an episiotomy after application of the blades (Chap. 29p. 580).

Technique

For midline episiotomy, fingers are insinuated between the crowning head and the perineum. The scissors are positioned at 6 o’clock on the vaginal opening and directed posteriorly (see Fig. 27-16). The incision length varies from 2 to 3 cm depending on perineal length and degree of tissue thinning. The incision is customized for specific delivery needs but should stop well before reaching the external anal sphincter. With mediolateral episiotomy, scissors are positioned at 7 o’clock or at 5 o’clock, and the incision is extended 3 to 4 cm toward the ipsilateral ischial tuberosity.

Differences between the two types of episiotomies are summarized in Table 27-2. Except for the important issue of third-and fourth-degree extensions, midline episiotomy is superior. Anthony and colleagues (1994) presented data from the Dutch National Obstetric Database of more than 43,000 deliveries. They found a more than fourfold decrease in severe perineal lacerations following mediolateral episiotomy compared with rates after midline incision. Proper selection of cases can minimize this one disadvantage. For example, if episiotomy is required during operative vaginal delivery, several studies have reported a protective effect from mediolateral episiotomy against higher-order perineal lacerations (de Leeuw, 2008; de Vogel, 2012; Hirsch, 2008).

TABLE 27-2. Midline versus Mediolateral Episiotomy

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Repair of Episiotomy or Perineal Laceration

Typically, episiotomy repair is deferred until the placenta has been delivered. This policy permits undivided attention to the signs of placental separation and delivery. A further advantage is that episiotomy repair is not interrupted or disrupted by the obvious necessity of delivering the placenta, especially if manual removal must be performed that may disrupt a newly repaired episiotomy. The major disadvantage is continuing blood loss until the repair is completed. Direct pressure from an applied gauze sponge will help to limit this loss.

For suitable repair, an understanding of perineal support and anatomy is necessary and is discussed in Chapter 2 (p. 21). Adequate analgesia is imperative, and Sanders and coworkers (2002) emphasized that women without regional analgesia can experience high levels of pain during perineal suturing. Again, local lidocaine can be used solely or as a supplement to bilateral pudendal nerve blockade. In those with epidural analgesia, additional dosing may be necessary.

There are many ways to repair an episiotomy incision, but hemostasis and anatomical restoration without excessive suturing are essential. A technique that commonly is employed for midline repair is shown in Figure 27-17. Some studies have found similar postoperative pain scores using either continuous or interrupted closure (Kindberg, 2008; Valenzuela, 2009). Others note less pain with continuous suturing (Kettle, 2012). Moreover, continuous suturing is faster and uses less suture material. Mornar and Perlow (2008) have shown that blunt needles are suitable and likely decrease the incidence of needlestick injuries. The suture material commonly used is 2–0 chromic catgut. Sutures made of polyglycolic acid derivatives are also frequently used. A decrease in postsurgical pain is cited as the major advantage of synthetic materials. Closures with these materials, however, occasionally require suture removal from the repair site because of pain or dyspareunia. According to Kettle and associates (2002), this disadvantage may be reduced using a rapidly absorbed polyglactin 910 (Vicryl Rapide).

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FIGURE 27-17 Repair of midline episiotomy. A. Disruption of the hymenal ring and bulbocavernosus and superficial transverse perineal muscles are seen within the diamond-shaped episiotomy incision. B.An anchor stitch is placed above the wound apex to begin a running closure. Absorbable 2–0 or 3–0 suture is used for continuous closure of the vaginal mucosa and submucosa with interlocking stitches. C.After closing the vaginal incision and reapproximating the cut margins of the hymenal ring, the needle and suture are positioned to close the perineal incision. D. A continuous closure with absorbable 2–0 or 3–0 suture is used to close the fascia and muscles of the incised perineum. This aids restoration of the perineal body for long-term support. E. The continuous suture is then carried upward as a subcuticular stitch. The final knot is tied proximal to the hymenal ring.

Repair of a mediolateral episiotomy is similar to a midline repair. The technique is shown in Figure 27-18.

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FIGURE 27-18 Mediolateral episiotomy repair. The vaginal mucosa is shown as already closed using 2–0 absorbable suture in a running interlocking stitch similar to that for midline repair. As illustrated, perineal reapproximation begins with reunion of bulbocavernosus and transverse perineal muscles. These will assist reestablishment of perineal body support. Distal to these muscles, abundant fat in the ischiorectal fossa is incorporated in the same running closure. A second layer atop this first perineal layer may be required to adequately close dead space. The skin is then closed with a subcuticular stitch as used for midline closure.

Fourth-Degree Laceration Repair

Two methods are used to repair a laceration involving the anal sphincter and rectal mucosa. The first is the end-to-end technique, which we prefer, and the second is the overlapping technique.

The end-to-end technique is shown in Figure 27-19. In all techniques that have been described, it is essential to approximate the torn edges of the rectal mucosa with sutures placed in the rectal muscularis approximately 0.5 cm apart. One suitable choice is 2–0 or 3–0 chromic gut. This muscular layer then is covered by reapproximation of the internal anal sphincter. Finally, the cut ends of the external anal sphincter are isolated, approximated, and sutured together end-to-end with three or four interrupted stitches. The remainder of the repair is the same as for a midline episiotomy.

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FIGURE 27-19 Layered repair of a fourth-degree perineal laceration. A. Approximation of the anorectal mucosa and submucosa in a running or interrupted fashion using fine absorbable suture such as 3–0 or 4–0 chromic or Vicryl. During this suturing, the superior extent of the anterior anal laceration is identified, and the sutures are placed through the submucosa of the anorectum approximately 0.5 cm apart down to the anal verge. B. A second layer is placed through the rectal muscularis using 3–0 Vicryl suture in a running or interrupted fashion. This “reinforcing layer” should incorporate the torn ends of the internal anal sphincter, which is identified as the thickening of the circular smooth muscle layer at the distal 2 to 3 cm of the anal canal. It can be identified as the glistening white fibrous structure lying between the anal canal submucosa and the fibers of the external anal sphincter (EAS). In many cases, the internal sphincter retracts laterally and must be sought and retrieved for repair. C. In overview, with traditional end-to-end approximation of the EAS, a suture is placed through the EAS muscle, and four to six simple interrupted 2–0 or 3–0 Vicryl sutures are placed at the 3, 6, 9, and 12 o’clock positions through the connective tissue capsule of the sphincter. The sutures through the inferior and posterior portions of the sphincter should be placed first to aid this part of the repair. To begin this portion of the closure, the disrupted ends of the striated EAS muscle and capsule are identified and grasped with Allis clamps. Suture is placed through the posterior wall of the EAS capsule. D. Sutures through the EAS (blue suture) and inferior capsule wall. E. Sutures to reapproximate the anterior and superior walls of the EAS capsule. The remainder of the repair is similar to that described for a midline episiotomy in Figure 27-17.

The overlapping technique is an alternative method to approximate the external anal sphincter. Data based on randomized controlled trials do not support that this method yields superior anatomical or functional results compared with those of the traditional end-to-end method (Farrell, 2012; Fitzpatrick, 2000).

We, as well as others, recommend perioperative antimicrobial prophylaxis for the reduction of infectious morbidity associated with higher-order perineal injury repair (Goldaber, 1993; Stock, 2013). A single dose of a second-generation cephalosporin is suitable, or clindamycin for penicillin-allergic women. Although such prophylaxis has some evidence-based support, the American College of Obstetricians and Gynecologists (2011) has concluded that this practice has not been extensively studied (Duggal, 2008; Stock, 2013). Postoperatively, stool softeners should be prescribed for a week, and enemas and suppositories should be avoided.

Unfortunately, normal function is not always ensured even with correct and complete surgical repair. Some women may experience continuing fecal incontinence caused by injury to the innervation of the pelvic floor musculature (Roberts, 1990).

Postepisiotomy Pain

Pudendal nerve blockade can aid relief of perineal pain postoperatively (Aissaoui, 2008). Locally applied ice packs help reduce swelling and allay discomfort. Topical application of 5-percent lidocaine ointment was not effective in relieving episiotomy or perineal laceration discomfort in one randomized trial (Minassian, 2002). Analgesics such as codeine give considerable relief. Because pain may be a signal of a large vulvar, paravaginal, or ischiorectal fossa hematoma or perineal cellulitis, these sites should be examined carefully if pain is severe or persistent. Management of these complications is discussed in Chapters 37 and 41 (p. 689 and p. 790). In addition to pain, urinary retention may complicate episiotomy recovery (Mulder, 2012). Its management is described in Chapter 36 (p. 676).

For those with second-degree or greater lacerations, intercourse is usually proscribed until after the first puerperal visit at 4 to 6 weeks. Signorello and coworkers (2001) surveyed 615 women 6 months postpartum and reported that those delivered with an intact perineum reported better sexual function compared with those who had perineal trauma. In another follow-up of 2490 women, Rådestad and associates (2008) reported delayed intercourse at 3 and 6 months, but not at 1 year, in women with and without perineal trauma.

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