CLASSIFICATION OF BREECH PRESENTATIONS
ROUTE OF DELIVERY
TERM AND PRETERM BREECH FETUS
MANAGEMENT OF LABOR AND DELIVERY
PARTIAL BREECH EXTRACTION
TOTAL BREECH EXTRACTION
ANALGESIA AND ANESTHESIA
EXTERNAL CEPHALIC VERSION
INTERNAL PODALIC VERSION
Near term, the fetus typically turns spontaneously to a cephalic presentation as the increasing bulk of the buttocks seeks the more spacious fundus. However, if the fetal buttocks or legs enter the pelvis before the head, the presentation is breech. This fetal lie is more common remote from term as each fetal pole is of similar bulk earlier in pregnancy (Fig. 28-1). That said, breech presentation persists at term in 3 to 4 percent of singleton deliveries. The annual rate of breech presentation at delivery in nearly 270,000 singleton newborns at Parkland Hospital has varied from only 3.3 to 3.9 percent during the past 30 years.
FIGURE 28-1 Prevalence of breech presentation by gestational age at delivery in 58,842 singleton pregnancies at the University of Alabama at Birmingham Hospitals 1991 to 2006. (Data courtesy of Dr. John Hauth and Ms. Sue Cliver.)
Current obstetrical thinking regarding vaginal delivery of the breech fetus has been tremendously influenced by results reported from the Term Breech Trial Collaborative Group (Hannah, 2000). This trial included 1041 women randomly assigned to planned cesarean and 1042 to planned vaginal delivery. In the planned vaginal delivery group, 57 percent were actually delivered vaginally. Planned cesarean delivery was associated with a lower risk of perinatal mortality compared with planned vaginal delivery—3 per 1000 versus 13 per 1000. Cesarean delivery was also associated with a lower risk of “serious” neonatal morbidity—1.4 versus 3.8 percent.
The reaction to these findings by the American College of Obstetricians and Gynecologists (2001) resulted in an abrupt decline in the rate of attempted vaginal breech deliveries. Since those times, however, a more moderate plan was reached for management of breech delivery.
Critics of the Term Breech Trial emphasized that most of the outcomes included in the “serious” neonatal morbidity composite did not actually portend long-term disability. Moreover, as data from countries with low perinatal mortality rates became available, they showed infrequent perinatal deaths, and rates did not differ significantly between mode-of-delivery groups. Also, only nulliparas were included in the Term Breech Trial, and fewer than 10 percent underwent radiological pelvimetry. And last, the 2-year outcomes for children born during the original multicenter trial showed that planned cesarean delivery was not associated with a reduction in the rate of death or developmental delay (Whyte, 2004). Some of the large studies reporting the safety and risks of vaginal delivery for the term breech singleton are discussed further on page 561.
These findings prompted the American College of Obstetricians and Gynecologists (2012b) to modify its stance on breech presentation, and it currently recommends that “the decision regarding the mode of delivery should depend on the experience of the health care provider” and that “planned vaginal delivery of a term singleton breech fetus may be reasonable under hospital-specific protocol guidelines.” This has been echoed by other obstetrical organizations (Carbonne, 2001; Kotaska, 2009; Royal College of Obstetricians and Gynaecologists, 2009).
CLASSIFICATION OF BREECH PRESENTATIONS
The varying relations between the lower extremities and buttocks of breech fetuses form the categories of frank, complete, and incomplete breech presentations. With a frank breech presentation, the lower extremities are flexed at the hips and extended at the knees, and thus the feet lie in close proximity to the head (Fig. 28-2). A complete breech differs in that one or both knees are flexed (Fig. 28-3). With incomplete breech presentation, one or both hips are not flexed, and one or both feet or knees lie below the breech, such that a foot or knee is lowermost in the birth canal (Fig. 28-4). A footling breech is an incomplete breech with one or both feet below the breech.
FIGURE 28-2 Frank breech presentation.
FIGURE 28-3 Complete breech presentation.
FIGURE 28-4 Incomplete breech presentation.
In perhaps 5 percent of term breech fetuses, the head may be in extreme hyperextension. These presentations have been referred to as the stargazer fetus, and in Britain as the flying foetus. With such hyperextension, vaginal delivery may result in injury to the cervical spinal cord. Thus, if present after labor has begun, this is an indication for cesarean delivery (Svenningsen, 1985).
Understanding the clinical settings that predispose to breech presentation can aid early recognition. Other than early gestational age, risk factors include abnormal amnionic fluid volume, multifetal gestation, hydrocephaly, anencephaly, uterine anomalies, placenta previa, fundal placental implantation, pelvic tumors, high parity with uterine relaxation, and prior breech delivery. Specifically, following one breech delivery, the recurrence rate for a second pregnancy with breech presentation was nearly 10 percent, and that for a subsequent third pregnancy was 27 percent (Ford, 2010). Prior cesarean delivery has also been described by some to increase twofold the incidence of breech presentation (Kalogiannidis, 2010; Vendittelli, 2008). Last, smoking may be a modifiable cause of this presentation (Rayl, 1996; Witkop, 2008).
Leopold maneuvers to ascertain fetal presentation are discussed in Chapter 22 (p. 438). With the first maneuver, the hard, round, ballottable fetal head may be found to occupy the fundus. The second maneuver indicates the back to be on one side of the abdomen and the small parts on the other. With the third maneuver, if not engaged, the breech is movable above the pelvic inlet. After engagement, the fourth maneuver shows the firm breech to be beneath the symphysis. The accuracy of this palpation varies (Lydon-Rochelle, 1993; Nassar, 2006). Thus, with suspected breech presentation—or any presentation other than cephalic—sonographic evaluation is indicated.
With a frank breech during vaginal examination, no feet are appreciated, but the fetal ischial tuberosities, sacrum, and anus are usually palpable. After further fetal descent, the external genitalia may also be distinguished. Especially when labor is prolonged, the fetal buttocks may become markedly swollen, rendering differentiation of a face and breech difficult. In some cases, the anus may be mistaken for the mouth and the ischial tuberosities for the malar eminences. With careful examination, however, the finger encounters muscular resistance with the anus, whereas the firmer, less yielding jaws are felt through the mouth. The finger, upon removal from the anus, may be stained with meconium. The mouth and malar eminences form a triangular shape, whereas the ischial tuberosities and anus lie in a straight line. With a complete breech, the feet may be felt alongside the buttocks. In footling presentations, one or both feet are inferior to the buttocks.
The fetal sacrum and its spinous processes are palpated also to establish position. As with cephalic presentations described in Chapter 22 (p. 434), fetal positions are designated as left sacrum anterior (LSA), right sacrum anterior (RSA), left sacrum posterior (LSP), right sacrum posterior (RSP), or sacrum transverse (ST) to reflect the relations of the fetal sacrum to the maternal pelvis.
ROUTE OF DELIVERY
Multiple factors aid determination of the best delivery route for a given mother-fetus pair. These include fetal characteristics, pelvic dimensions, coexistent pregnancy complications, operator experience, patient preference, and hospital capabilities.
Term and Preterm Breech Fetus
Although sharing the similarity of presentation, preterm breech fetuses have distinct risks related to immaturity compared with their term breech counterparts. Accordingly, separation of term and preterm breech fetuses for discussion allows a more accurate evaluation of information.
Term Breech Fetus
Data regarding superior perinatal outcomes for planned cesarean delivery of a singleton term breech are conflicting. As described earlier (p. 558), the Term Breech Trial reported lower neonatal morbidity and mortality rates with planned cesarean delivery for breech presentation. Additional data favoring cesarean delivery comes from the World Health Organization (Lumbiganon, 2010). From their evaluation of more than 100,000 deliveries from nine participating Asian countries, they reported improved perinatal outcomes associated with planned cesarean compared with planned vaginal delivery of the term breech fetus. Other studies have evaluated neonatal outcome with cesarean delivery and also found lowered neonatal morbidity and mortality rates (Hartnack Tharin, 2011; Mailàth-Pokorny, 2009; Rietberg, 2005; Swedish Collaborative Breech Study Group, 2005).
In contrast, the Presentation et Mode d’Accouchement—which translates as presentation and mode of delivery (PREMODA)—study showed no differences in corrected neonatal mortality rates and neonatal outcomes according to delivery mode (Goffinet, 2006). This French prospective observational study involved more than 8000 women with term breech singletons. Strict criteria were used to select 2526 of these for planned vaginal delivery, and 71 percent of that group were delivered vaginally. Similarly, data from the Lille Breech Study Group in France showed no excessive morbidity in term breech singletons delivered vaginally provided strict fetal biometric and maternal pelvimetry parameters were applied (Michel, 2011). Other smaller studies also support these findings as long as guidelines are part of the selection process (Alarab, 2004; Albrechtsen, 1997; Giuliani, 2002; Toivonen, 2012). Long-term evidence in support of vaginal breech delivery comes from Eide and associates (2005). These researchers analyzed intelligence testing scores of more than 8000 men delivered breech and found no differences in intellectual performance in those delivered vaginally or by cesarean.
Despite evidence on both sides of the debate, at least in this country, rates of planned vaginal delivery attempts continue to decline (Hehir, 2012). And as predicted, the number of skilled operators able to safely select and vaginally deliver breech fetuses continues to dwindle (Chinnock, 2007). Moreover, obvious medicolegal concerns makes physician training in such deliveries difficult. In response, some institutions have developed birth simulators to improve resident competence in vaginal breech delivery (Deering, 2006; Maslovitz, 2007).
Preterm Breech Fetus
Although there are no randomized studies regarding delivery of the preterm breech fetus, planned cesarean delivery appears to confer a survival advantage. Reddy and associates (2012) reported data from an National Institutes of Health retrospective multicenter cohort study involving 208,695 deliveries between 24 and 32 weeks’ gestation. For breech fetuses within these gestational ages, attempting vaginal delivery yielded a low completion rate, and those completed were associated with higher neonatal mortality rates compared with planned cesarean delivery. Other studies have reported similar findings (Demirci, 2012; Lee, 1998; Muhuri, 2006). There are, however, a few smaller studies that describe no improved survival rate in fetuses at earlier gestational ages—24 to 29 weeks—delivered by planned cesarean (Kayem, 2008; Stohl, 2011).
There are limited data regarding any preferable delivery route for preterm breech fetuses between 32 and 37 weeks. In these cases, fetal weight rather than gestational age is likely most important. The Maternal Fetal Medicine Committee of the Society of Obstetricians and Gynaecologists of Canada (SOGC) recommend that vaginal breech delivery is reasonable when the estimated fetal weight is > 2500 g (Kotaska, 2009).
Maternal Morbidity and Mortality
Increased rates of maternal and perinatal morbidity can be anticipated with breech presentations. For the mother, with either cesarean or vaginal delivery, genital tract laceration can be problematic. With cesarean delivery, added stretching of the lower uterine segment by forceps or by a poorly molded fetal head can extend hysterotomy incisions. With vaginal delivery, especially with a thinned lower uterine segment, delivery of the aftercoming head through an incompletely dilated cervix or application of forceps may cause vaginal wall or cervical lacerations. Manipulations may also extend an episiotomy, create deep perineal tears, and increase infection risks. Anesthesia sufficient to induce appreciable uterine relaxation during vaginal delivery may cause uterine atony and in turn, postpartum hemorrhage. Death is a rare complication, but rates appear higher in those with planned cesarean delivery for breech presentation—a case fatality rate of 0.47 maternal deaths per 1000 births (Schutte, 2007). Last, as described in Chapter 30 (p. 588), the risks associated with vaginal breech delivery are balanced against general cesarean delivery risks, which include those associated with vaginal birth after cesarean (VBAC) or those with repeated cesarean hysterotomy.
Perinatal Morbidity and Mortality
Preterm delivery is a common association, and there is an increased rate of congenital anomalies. In addition, birth trauma, although uncommon, can contribute to death of the breech fetus. Importantly, these are seen both with vaginal as well as cesarean delivery. Some of the more common injuries are fractures of the humerus, clavicle, and femur (Canpolat, 2010; Matsubara, 2008). In some cases, traction may separate scapular, humeral, or femoral epiphyses.
Rare traumatic injuries may involve bony or soft tissues. Neonatal perineal tears have been reported from fetal scalp electrodes (Freud, 1993). Upper extremity paralysis—Erb or Duchenne—may follow brachial plexus stretching (Al-Qattan, 2010). When the fetus is extracted through a contracted pelvis, spoon-shaped depressions or actual fractures of the skull may result. The spinal cord may be injured or vertebra fractured if great force is employed (Vialle, 2007). Hematomas of the sternocleidomastoid muscles occasionally develop after delivery, although they usually disappear spontaneously. Last, testicular injury may follow breech delivery (Mathews, 1999). These are discussed in further detail in Chapter 33 (p. 645).
Compared with cephalic presentation, umbilical cord prolapse is more frequent with breech fetuses. Huang and coworkers (2012) analyzed 40 cases of prolapse and reported that half were associated with malpresentation or vaginal delivery of a second twin.
Some perinatal outcomes may be inherent to the breech position rather than delivery. For example, development of hip dysplasia is more common in breech compared with cephalic presentation and is unaffected by delivery mode (de Hundt, 2012; Fox, 2010; Ortiz-Neira, 2012).
In many fetuses—especially those that are preterm—the breech is smaller than the aftercoming head. Moreover, unlike cephalic presentations, the head of a breech-presenting fetus does not undergo appreciable molding during labor. Thus, to avoid head entrapment following delivery of the breech, pelvic dimensions should be assessed before vaginal delivery. In addition, fetal size, type of breech, and degree of neck flexion or extension should be identified. To evaluate these, several imaging techniques can be used.
In most cases, sonographic fetal evaluation will have been performed as part of prenatal care. If not, gross fetal abnormalities, such as hydrocephaly or anencephaly, can be rapidly ascertained with sonography. This will identify many fetuses not suitable for vaginal delivery and will help to ensure that a cesarean delivery is not performed under emergency conditions for an anomalous fetus with no chance of survival.
Head flexion can usually also be determined sonographically, and for vaginal delivery, the fetal head should not be extended (Fontenot, 1997; Rojansky, 1994). If imaging is uncertain, then simple two-view radiography of the abdomen is useful to define head inclination. The sonographic accuracy of fetal weight estimation does not appear limited by breech presentation (McNamara, 2012). Although variable, many protocols use fetal weights < 2500 g and > 3800 to 4000 g or evidence of growth restriction as exclusion criteria for planned vaginal delivery (Azria, 2012; Kotaska, 2009). Similarly, a biparietal diameter (BPD) > 90 to 100 mm is often considered exclusionary (Giuliani, 2002; Roman, 2008).
This assessment of the bony pelvis before vaginal delivery may be completed with one-view computed tomography (CT), magnetic resonance imaging, or plain film radiographs. Although there are no comparative data among these modalities for pelvimetry, computed tomography is favored due to its accuracy, low radiation dose, and widespread availability (Thomas, 1998). At Parkland Hospital, we use CT pelvimetry when possible to assess the critical dimensions of the pelvis (Chap. 2, p. 32). Although variable, some suggest specific measurements to permit a planned vaginal delivery: inlet anteroposterior diameter ≥ 105 mm; inlet transverse diameter ≥ 120 mm; and midpelvic interspinous diameter ≥ 100 mm (Azria, 2012; Vendittelli, 2006). Others use maternal-fetal biometry correlation. Appropriate values include: the sum of the inlet obstetrical conjugate minus the fetal BPD is ≥ 15 mm; the inlet transverse diameter minus the BPD is ≥ 25 mm; and the midpelvis interspinous diameter minus the BPD is ≥ 0 mm (Michel, 2011).
As outlined by the American College of Obstetricians and Gynecologists (2012b), risks versus benefits are weighed and discussed with the patient. If possible, this is preferably done before admission. A diligent search is made for any other complications, actual or anticipated, that might warrant cesarean delivery. Common circumstances are listed in Table 28-1. For a favorable outcome with any breech delivery, at the very minimum, the birth canal must be sufficiently large to allow passage of the fetus without trauma. The cervix must be fully dilated, and if not, then a cesarean delivery nearly always is the more appropriate method of delivery if suspected fetal compromise develops.
TABLE 28-1. Factors Favoring Cesarean Delivery of the Breech Fetus
Lack of operator experience
Patient request for cesarean delivery
Large fetus: > 3800 to 4000 g
Apparently healthy and viable preterm fetus either with active labor or with indicated delivery
Severe fetal-growth restriction
Fetal anomaly incompatible with vaginal delivery
Prior perinatal death or neonatal birth trauma
Incomplete or footling breech presentation
Pelvic contraction or unfavorable pelvic shape determined clinically or with pelvimetry
Prior cesarean delivery
MANAGEMENT OF LABOR AND DELIVERY
Methods of Vaginal Delivery
There are important fundamental differences between labor and delivery in cephalic and breech presentations. With a cephalic presentation, once the head is delivered, the rest of the body typically follows without difficulty. With a breech, however, successively larger and less compressible parts are born. Spontaneous complete expulsion of the fetus that presents as a breech, as subsequently described, is seldom accomplished successfully. Therefore, as a rule, vaginal delivery requires skilled participation for a favorable outcome.
There are three general methods of breech delivery through the vagina:
1. Spontaneous breech delivery. The fetus is expelled entirely spontaneously without any traction or manipulation other than support of the newborn.
2. Partial breech extraction. The fetus is delivered spontaneously as far as the umbilicus, but the remainder of the body is extracted or delivered with operator traction and assisted maneuvers, with or without maternal expulsive efforts.
3. Total breech extraction. The entire body of the fetus is extracted by the obstetrician.
Labor Induction and Augmentation
Induction or augmentation of labor in women with a breech presentation is controversial, and data are limited. Marzouk and associates (2011) found similar perinatal neonatal outcomes with spontaneous labor or with cervical preparation and induced labor. In many studies, improved rates of successful vaginal delivery and neonatal outcome are associated with orderly labor progression. Thus, some protocols avoid augmentation, whereas others recommend it only for hypotonic contractions (Alarab, 2004; Kotaska, 2009). In women with a viable fetus, at Parkland Hospital, we attempt amniotomy induction but prefer cesarean delivery instead of oxytocin induction or augmentation.
Management of Labor
On arrival, rapid assessment should be made to establish the status of the membranes, labor, and fetal condition. Surveillance of fetal heart rate and uterine contractions begins at admission, and immediate recruitment of necessary staff should include: (1) an obstetrician skilled in the art of breech extraction, (2) an associate to assist with the delivery, (3) anesthesia personnel who can ensure adequate analgesia or anesthesia when needed, and (4) an individual trained in newborn resuscitation.
For the mother, an intravenous catheter is inserted, and crystalloid infusion begun. Emergency induction of anesthesia or maternal resuscitation following hemorrhage from lacerations or from uterine atony are but two of many reasons that may require immediate intravenous access.
Assessment of cervical dilatation and effacement and the station of the presenting part is essential for planning the route of delivery. If labor is too far advanced, there may not be sufficient time to obtain pelvimetry. This alone, however, should not force the decision for cesarean delivery. Commonly, satisfactory progress in labor is the best indicator of pelvic adequacy (Biswas, 1993; Nwosu, 1993). Sonographic fetal biometry and assessment of head flexion are completed. And if not performed as part of earlier prenatal care, fetal anatomy is evaluated. Ultimately, the choice of abdominal or vaginal delivery is based on factors discussed earlier and listed in Table 28-1.
For managing labor and delivery of a breech fetus, additional help is required. One-on-one nursing is ideal during labor because of the risk of cord prolapse or occlusion, and physicians must be readily available for such emergencies. Guidelines for monitoring the high-risk fetus are applied as discussed in Chapter 24 (p. 497). During the first stage of labor, the fetal heart rate is recorded at least every 15 minutes. Most clinicians prefer continuous electronic monitoring. If a nonreassuring fetal heart rate pattern develops, then a decision must be made regarding the necessity of cesarean delivery.
When membranes are ruptured, either spontaneously or artificially, the cord prolapse risk is appreciable and is increased when the fetus is small or when the breech is not frank (Dilbaz, 2006; Erdemoglu, 2010). Therefore, a vaginal examination should be performed following rupture to exclude prolapse, and special attention should be directed to the fetal heart rate for the first 5 to 10 minutes following membrane rupture.
Cardinal Movements with Breech Delivery
Engagement and descent of the breech usually take place with the bitrochanteric diameter in one of the oblique pelvic diameters. The anterior hip usually descends more rapidly than the posterior hip, and when the resistance of the pelvic floor is met, internal rotation of 45 degrees usually follows, bringing the anterior hip toward the pubic arch and allowing the bitrochanteric diameter to occupy the anteroposterior diameter of the pelvic outlet. If the posterior extremity is prolapsed, however, it, rather than the anterior hip, rotates to the symphysis pubis.
After rotation, descent continues until the perineum is distended by the advancing breech, and the anterior hip appears at the vulva. By lateral flexion of the fetal body, the posterior hip then is forced over the perineum, which retracts over the fetal buttocks, thus allowing the infant to straighten out when the anterior hip is born. The legs and feet follow the breech and may be born spontaneously or require aid.
After the birth of the breech, there is slight external rotation, with the back turning anteriorly as the shoulders are brought into relation with one of the oblique diameters of the pelvis. The shoulders then descend rapidly and undergo internal rotation, with the bisacromial diameter occupying the anteroposterior plane. Immediately following the shoulders, the head, which is normally sharply flexed on the thorax, enters the pelvis in one of the oblique diameters and then rotates in such a manner as to bring the posterior portion of the neck under the symphysis pubis. The head is then born in flexion.
The breech may engage in the transverse diameter of the pelvis, with the sacrum directed anteriorly or posteriorly. The mechanism of labor in the transverse position differs only in that internal rotation is through an arc of 90 rather than 45 degrees. Infrequently, rotation occurs in such a manner that the back of the fetus is directed posteriorly instead of anteriorly. Such rotation should be prevented if possible. Although the head may be delivered by allowing the chin and face to pass beneath the symphysis, the slightest traction on the body may cause extension of the head, which increases the diameter of the head that must pass through the pelvis.
Partial Breech Extraction
With all breech deliveries, unless there is considerable relaxation of the perineum, an episiotomy should be made and is an important adjunct to delivery. Ideally, the breech is allowed to deliver spontaneously to the umbilicus. Delivery is easier, and in turn, morbidity and mortality rates are, at least intuitively, lower. Delivery of the breech draws the umbilicus and attached cord into the pelvis, which stretches and compresses the cord. Therefore, once the breech has passed beyond the vaginal introitus, the abdomen, thorax, arms, and head must be delivered promptly either spontaneously or assisted, as described here.
The posterior hip will deliver, usually from the 6 o’clock position, and often with sufficient pressure to evoke passage of thick meconium (Fig. 28-5). The anterior hip then delivers, followed by external rotation to a sacrum anterior position. The mother should be encouraged to continue to push. As the fetus continues to descend, the legs are sequentially delivered by splinting the medial aspect of each femur with the operator’s fingers positioned parallel to each femur, and by exerting pressure laterally to sweep each leg away from the midline.
FIGURE 28-5 The hips of the frank breech are delivering over the perineum. The anterior hip usually is delivered first.
Following delivery of the legs, the fetal bony pelvis is grasped with both hands, using a cloth towel moistened with warm water. The fingers should rest on the anterior superior iliac crests and the thumbs on the sacrum, minimizing the chance of fetal abdominal soft tissue injury (Fig. 28-6). Maternal expulsive efforts are used in conjunction with downward traction to effect delivery.
FIGURE 28-6 Delivery of the body. The hands are applied, but not above the pelvic girdle. With thumbs over the sacrum, gentle downward traction is accomplished until the scapulas are clearly visible.
A cardinal rule in successful breech extraction is to employ steady, gentle, downward traction until the lower halves of the scapulas are delivered, making no attempt at delivery of the shoulders and arms until one axilla becomes visible. As the scapulas become visible, the fetal back tends to turn spontaneously toward the side of the mother to which it was originally directed. The appearance of one axilla indicates that the time has arrived for shoulder delivery. It makes little difference which shoulder is delivered first, and there are two methods for their delivery. In the first method, with the scapulas visible, the trunk is rotated in such a way that the anterior shoulder and arm appear at the vulva and can easily be released and delivered first (Fig. 28-7). The body of the fetus is then rotated 180 degrees in the reverse direction to deliver the other shoulder and arm (Fig. 28-8).
FIGURE 28-7 Clockwise rotation of the fetal pelvis and abdomen 90 degrees brings the sacrum from anterior to left sacrum transverse (LST). Simultaneously, the application of gentle downward traction effects delivery of the scapula (A) and arm (B–D).
FIGURE 28-8 Counterclockwise rotation from right sacrum anterior (RSA) to right sacrum transverse (RST) along with gentle downward traction effects delivery of the right scapula.
The second method is employed if trunk rotation is unsuccessful. With this maneuver, the posterior shoulder is delivered first. For this, the feet are grasped in one hand and drawn upward over the inner thigh of the mother, toward which the ventral surface of the fetus is directed (Fig. 28-9). In this manner, leverage is exerted on the posterior shoulder, which slides out over the perineal margin, usually followed by the arm and hand. Then, by depressing the body of the fetus, the anterior shoulder emerges beneath the pubic arch, and the arm and hand usually follow spontaneously.
FIGURE 28-9 As breech extraction continues, upward traction is employed with the fetus drawn to the mother’s left inner thigh, thus effecting delivery of the posterior shoulder. This is followed by delivery of the posterior arm. The fetal body is then depressed and delivery of the anterior shoulder follows.
These rotational and downward traction maneuvers will decrease the persistence of nuchal arms, which can prevent descent and may result in a traumatic delivery. These maneuvers are frequently most easily effected with the operator at the level of the maternal pelvis and with one knee on the floor.
After both shoulders are delivered, the back of the fetus tends to rotate spontaneously in the direction of the symphysis. If upward rotation fails to occur, it is completed by manual rotation of the body. Delivery of the head may then be accomplished.
Unfortunately, the process is not always so simple, and it is sometimes necessary to assist delivery of the arms. There is more space available in the posterior and lateral segments of the normal pelvis than elsewhere. Therefore, in difficult cases, the posterior arm should be freed first. Because the corresponding axilla is already visible, upward traction on the feet is continued, and two fingers of the other hand are passed along the humerus until the elbow is reached (see Fig. 28-9). The fingers are placed parallel to the humerus and used to splint the arm, which is swept downward and delivered through the vulva. To deliver the anterior arm, depression of the fetal body is sometimes all that is required to allow the anterior arm to slip out spontaneously. In other instances, the anterior arm can be swept down over the thorax using two of the operator’s fingers as a splint.
In some cases, the body must be held with the thumbs over the scapulas and rotated to bring the undelivered shoulder near the closest sacrosciatic notch. The legs then are carried upward to bring the ventral surface of the fetus to the opposite inner thigh of the mother. Subsequently, the arm can be delivered posteriorly as described previously. If the arms have become extended over the head, their delivery, although more difficult, usually can be accomplished by the maneuvers just described. In so doing, particular care must be taken by the operator to carry his or her fingers up to the elbow and to use them as a splint to prevent fracture of the fetal humerus.
As just mentioned, one or both fetal arms occasionally may be found around the back of the neck—the nuchal arm—and impacted at the pelvic inlet. In this situation, delivery is more difficult. If the nuchal arm cannot be freed in the manner just described, extraction may be aided, especially with a single nuchal arm, by rotating the fetus through a half circle in such a direction that the friction exerted by the birth canal will serve to draw the elbow toward the face (Fig. 28-10). Should rotation of the fetus fail to free the nuchal arm(s), it may be necessary to push the fetus upward in an attempt to release it. If the rotation is still unsuccessful, the nuchal arm often is extracted by hooking a finger(s) over it and forcing the arm over the shoulder, and down the ventral surface for delivery of the arm. In this event, fracture of the humerus or clavicle is common.
FIGURE 28-10 Reduction of nuchal arm being accomplished by rotating the fetus through half a circle counterclockwise so that the friction exerted by the birth canal will draw the elbow toward the face.
Modified Prague Maneuver
Rarely, the back of the fetus fails to rotate to the anterior. In this situation, rotation of the back to the anterior may be achieved by using stronger traction on the fetal legs or bony pelvis. If the back still remains oriented posteriorly, extraction may be accomplished using the Mauriceau maneuver, described next, and delivering the fetus back down. If this is impossible, the fetus still may be delivered using the modified Prague maneuver, which, as practiced today, consists of two fingers of one hand grasping the shoulders of the back-down fetus from below while the other hand draws the feet up and over the maternal abdomen (Fig. 28-11).
FIGURE 28-11 Delivery of the aftercoming head using the modified Prague maneuver necessitated by failure of the fetal trunk to rotate anteriorly.
Delivery of the Aftercoming Head
Mauriceau Maneuver. Normally, the fetal head may be extracted with forceps or by one of several maneuvers. With the Mauriceau maneuver, the index and middle finger of one hand are applied over the maxilla, to flex the head, while the fetal body rests on the palm of the hand and forearm (Fig. 28-12). The operator’s forearm is straddled by the fetal legs. Two fingers of the other hand then are hooked over the fetal neck, and grasping the shoulders, downward traction is concurrently applied until the suboccipital region appears under the symphysis. Gentle suprapubic pressure simultaneously applied by an assistant helps keep the head flexed. The body then is elevated toward the maternal abdomen, and the mouth, nose, brow, and eventually the occiput emerge successively over the perineum. With this maneuver, the operator uses both hands simultaneously and in tandem to exert continuous downward gentle traction simultaneously on the fetal neck and on the maxilla. At the same time, appropriate suprapubic pressure is applied by an assistant (see Fig. 28-12).
FIGURE 28-12 A. Delivery of the aftercoming head using the Mauriceau maneuver. Note that as the fetal head is being delivered, flexion of the head is maintained by suprapubic pressure provided by an assistant. B. Pressure on the maxilla is applied simultaneously by the operator as upward and outward traction is exerted.
Forceps to Aftercoming Head. Specialized forceps can also be used to deliver the aftercoming head. Piper forceps, shown in Figure 28-13, or divergent Laufe forceps may be applied electively or when the Mauriceau maneuver cannot be accomplished easily. The blades of the forceps should not be applied to the aftercoming head until it has been brought into the pelvis by gentle traction, combined with suprapubic pressure, and is engaged. Suspension of the body of the fetus in a towel effectively holds the fetus up and helps keep the arms and cord out of the way as the forceps blades are applied.
FIGURE 28-13 Piper forceps for delivery of the aftercoming head. A. The fetal body is held elevated using a warm towel and the left blade of forceps is applied to the aftercoming head. B. The right blade is applied with the body still elevated. C. Forceps delivery of the aftercoming head. Note the direction of movement shown by the arrow.
Because the forceps blades are directed upward from the level of the perineum, some choose to apply them from a one-knee kneeling position. Piper forceps have a downward arch in the shank to accommodate the fetal body and lack a pelvic curve. This shape permits a direct application of the cephalic curve of the blade along the length of the maternal vagina and fetal parietal bone. The blade to be placed on the maternal left is held in the operator’s left hand. The right hand slides between the fetal head and left maternal vaginal sidewall to guide the blade inward and around the parietal bone. The opposite blade mirrors this application. Once in place, the blades are articulated, and the fetal body rests across the shanks. The head is delivered by pulling gently outward and raising the handle simultaneously. This rolls the face over the perineum, while the occiput remains beneath the symphysis until after the brow delivers. Ideally, the head and body move in unison to minimize trauma.
Entrapment of the Aftercoming Head. Occasionally—especially with a small preterm fetus—the incompletely dilated cervix will constrict around the neck and impede delivery of the aftercoming head. At this point, it must be assumed that there is significant and even total cord compression, and thus time management is essential. With gentle traction on the fetal body, the cervix, at times, may be manually slipped over the occiput. If this is not successful, then Dührssen incisions as shown in Figure 28-14 may be necessary. Other alternatives include intravenous nitroglycerin—typically 100 μg—to provide cervical relaxation (Dufour, 1997; Wessen, 1995). There is, however, no compelling evidence of its efficacy for this purpose. General anesthesia with halogenated agents is another option.
FIGURE 28-14 Dührssen incision being cut at 2 o’clock, which is followed by a second incision at 10 o’clock. Infrequently, an additional incision is required at 6 o’clock. The incisions are so placed as to minimize bleeding from the laterally located cervical branches of the uterine artery. After delivery, the incisions are repaired as described in Chapter 41 (p. 790).
As a last resort, replacement of the fetus higher into the vagina and uterus, followed by cesarean delivery, can be used to rescue an entrapped breech fetus that cannot be delivered vaginally. This maneuver was described for the protruding head with intractable shoulder dystocia and is termed the Zavanelli maneuver as described by Sandberg (1988). It was subsequently reported by Steyn and Pieper (1994) to be used to deliver the entrapped aftercoming head in a 2590-g breech fetus. Sandberg (1999) reviewed 11 breech deliveries in which this maneuver was used.
Symphysiotomy is also used to aid delivery of an entrapped aftercoming head. Using local analgesic, this operation surgically divides the intervening symphyseal cartilage and much of its ligamentous support to widen the symphysis pubis up to 2.5 cm (Basak, 2011). Lack of operator training and potentially serious maternal pelvic or urinary tract injury explain its rare use in the United States. That said, if cesarean section is not available or unsafe for the mother, symphysiotomy may be lifesaving for both mother and baby (Hofmeyr, 2012).
Total Breech Extraction
Complete or Incomplete Breech
At times, total extraction of a complete or incomplete breech may be required. A hand is introduced through the vagina, and both fetal feet are grasped. The ankles are held with the second finger lying between them. With gentle traction, the feet are brought through the introitus. If difficulty is experienced in grasping both feet, first one foot should be drawn into the vagina but not through the introitus, and then the other foot is advanced in a similar fashion. Now both feet are grasped and pulled through the vulva simultaneously (Fig. 28-15).
FIGURE 28-15 Complete breech extraction begins with traction on the feet and ankles.
As the legs begin to emerge through the vulva, downward gentle traction is continued. As the legs emerge, successively higher portions are grasped, first the calves and then the thighs. When the breech appears at the vaginal outlet, gentle traction is applied until the hips are delivered. As the buttocks emerge, the back of the fetus usually rotates to the anterior. The thumbs are then placed over the sacrum and the fingers over the hips, and breech extraction is completed, as described for partial breech extraction (p. 564). During cesarean delivery, these maneuvers are also used during delivery of a complete, incomplete, or footling breech through the hysterotomy incision.
During complete extraction of a frank breech, moderate traction is exerted by a finger in each groin and aided by a generous episiotomy (Fig. 28-16). Once the breech is pulled through the introitus, the steps described for partial breech extraction are then completed (p. 564). These maneuvers are also used during cesarean delivery of the frank breech through the hysterotomy incision.
FIGURE 28-16 A. Extraction of frank breech using fingers in groins. B. Once the hips are delivered, each hip and knee is flexed to deliver them from the vagina.
If moderate traction does not effect delivery, then vaginal delivery can be accomplished only by breech decomposition. This procedure involves manipulation within the birth canal to convert the frank breech into a footling breech. It is accomplished more readily if the membranes have ruptured only recently, and it becomes extremely difficult if there is minimal amnionic fluid. In such cases, the uterus may have become tightly contracted around the fetus. Pharmacological relaxation by general anesthesia, intravenous magnesium sulfate, or a betamimetic agent such as terbutaline, 250 μg subcutaneously, may be required.
Breech decomposition is accomplished by the maneuver attributed to Pinard (1889). It aids in bringing the fetal feet within reach of the operator. As shown in Figure 28-17, two fingers are carried up along one extremity to the knee to push it away from the midline. Spontaneous flexion usually follows, and the foot of the fetus is felt to impinge on the back of the hand. The fetal foot then may be grasped and brought down.
FIGURE 28-17 Frank breech decomposition using the Pinard maneuver. Two fingers are inserted along one extremity to the knee, which is then pushed away from the midline after spontaneous flexion. Traction is used to deliver a foot into the vagina.
ANALGESIA AND ANESTHESIA
Continuous epidural analgesia, as described in Chapter 25 (p. 509), is advocated by some as ideal for women in labor with a breech presentation. This may increase the need for labor augmentation and may prolong second-stage labor (Chadha, 1992; Confino, 1985). These potential disadvantages must be weighed against the advantages of better pain relief and increased pelvic relaxation should extensive manipulation be required. Analgesia must be sufficient for episiotomy, for breech extraction, and for Piper forceps application. Nitrous oxide plus oxygen inhalation provides further relief from pain. If general anesthesia is required, it must be induced quickly.
Anesthesia for breech decomposition and extraction must provide sufficient relaxation to allow intrauterine manipulations. Although successful decomposition has been accomplished using epidural or spinal analgesia, increased uterine tone may render the operation more difficult. Under such conditions, general anesthesia with a halogenated agent may be required.
With this procedure, fetal presentation is altered by physical manipulation, either substituting one pole of a longitudinal presentation for the other, or converting an oblique or transverse lie into a longitudinal presentation. According to whether the head or breech is made the presenting part, the operation is designated cephalic or podalic version, respectively. With external version, the manipulations are performed exclusively through the abdominal wall. With internal version, they are accomplished inside the uterine cavity.
External Cephalic Version
For breech fetuses near term, the American College of Obstetricians and Gynecologists (2012a,b) recommends that version should be offered and attempted whenever possible. Its success rate ranges from 35 to 86 percent, with an average of 58 percent. For women with a transverse lie, the overall success rate is significantly higher.
In general, external version is attempted before labor in a woman who has reached 36 weeks’ gestation with a breech fetus. Before this time, a breech presentation still has a high likelihood of correcting spontaneously. And, if performed too early, time may allow a return back to breech (Bogner, 2012). Last, if version causes a need for immediate delivery, complications of iatrogenic preterm delivery generally are not severe.
Version is contraindicated if vaginal delivery is not an option. Examples include placenta previa or nonreassuring fetal status. Other contraindications include rupture of membranes, known uterine malformation, multifetal gestation, and recent uterine bleeding. As discussed in Chapter 31 (p. 616), prior uterine incision is a relative contraindication. In a few small studies, external version was not associated with uterine rupture (Abenhaim, 2009; Sela, 2009). At Parkland Hospital, external version is not attempted in these women, but larger studies are needed.
Several factors can improve the chances of a successful version attempt. These include multiparity, abundant amnionic fluid, unengaged presenting part, fetal size 2500 to 3000 g, posterior placenta, and nonobese patient (Buhimschi, 2011; de Hundt, 2012; Kok, 2008, 2009, 2011).
Patient counseling includes projected success rates, conversion back to breech, and risks of the procedure itself. Risks include placental abruption, uterine rupture, fetomaternal hemorrhage, alloimmunization, preterm labor, fetal compromise, and even death. Most worrisome is the report by Stine and coworkers (1985) of a maternal death due to amnionic fluid embolism. That said, fetal deaths are rare, serious complication rates are typically very low, and emergent cesarean rates are 0.5 percent or less (Collaris, 2004; Collins, 2007; Grootscholten, 2008).
Importantly, even after successful version, several reports suggest that the cesarean delivery rate does not completely revert to the baseline for vertex presentations. Specifically, dystocia, malpresentation, and nonreassuring fetal heart patterns may be more common in these fetuses despite successful version (Chan, 2004; Vézina, 2004).
External cephalic version should be carried out in an area that has ready access to a facility equipped to perform an emergency cesarean delivery (American College of Obstetricians and Gynecologists, 2012a). Sonographic examination is performed to confirm nonvertex presentation, document amnionic fluid volume adequacy, exclude obvious fetal anomalies if not done previously, and identify placental location. External monitoring is performed to assess fetal heart rate reactivity. Anti-D immune globulin is given to Rh-D negative women.
A forward roll of the fetus usually is attempted first. Each hand grasps one fetal pole, and the fetal buttocks are elevated from the maternal pelvis and displaced laterally (Fig. 28-18). The buttocks are then gently guided toward the fundus, while the head is directed toward the pelvis. If the forward roll is unsuccessful, then a backward flip is attempted. Version attempts are discontinued for excessive discomfort, persistently abnormal fetal heart rate, or after multiple failed attempts. Failure is not always absolute. Ben-Meir and colleagues (2007) reported a spontaneous version rate of 7 percent among 226 failed versions—2 percent among nulliparas and 13 percent among parous women.
FIGURE 28-18 External cephalic version. With an attempted forward roll, clockwise pressure is exerted against the fetal poles.
If version is successful, the nonstress test is repeated until a normal test result is obtained. If version is completed before 39 weeks’ gestation, then awaiting spontaneous labor and fetal maturity is preferred.
Existing evidence may support the use of tocolytic agents during external version attempts (American College of Obstetricians and Gynecologists, 2012a). Agents investigated include betamimetics, such as terbutaline, ritodrine, or salbutamol; calcium-channel blockers, such as nifedipine; and nitric oxide donors, such as nitroglycerin. Most randomized investigations have evaluated betamimetics. In one such trial, Fernandez and coworkers (1996) reported that the success rate with subcutaneous terbutaline—52 percent—was significantly higher than without—27 percent. Other studies of betamimetics support their efficacy, although not universally (Marquette, 1996; Robertson, 1987; Vani, 2009). There is less evidence to support the use of nifedipine and nitroglycerin (Cluver, 2012; Wilcox, 2011). Our policy at Parkland Hospital is to administer 250 μg of terbutaline subcutaneously to most women before attempted version. When maternal tachycardia—a known side effect of terbutaline—is noted, then the version attempt is begun.
Epidural analgesia has been reported to increase version success rates (Mancuso, 2000; Schorr, 1997). But Sullivan and associates (2009) noted no improvement with combined spinal-epidural analgesia. In two small randomized trials, Weiniger and associates (2007, 2010) reported that spinal analgesia increased version success rate. In the trials by Dugoff (1999) and Delisle (2003) and their colleagues, spinal analgesia was not of benefit. According to the American College of Obstetricians and Gynecologists (2012a), there is not enough consistent evidence to recommend conduction analgesia routinely for external version.
With the exception of rare severe complications, Collaris and Oei (2004) concluded that external cephalic version is safe. One caveat was that complications were more common when conduction analgesia was used. Use of nitrous oxide or conduction analgesia was associated with twice as many abnormal fetal heart rate tracings. Moreover, vaginal bleeding and procedure-related emergency cesarean deliveries were increased tenfold. These reviewers concluded that diminished pain in these women likely encouraged overzealous application of force during the version attempts. In another small study, however, Suen and associates (2012) showed that the force applied during version under spinal analgesia was actually less.
There are some unconventional interventions that have been used to help effect version. Moxibustion is a traditional Chinese medicine technique that burns a cigarette-shaped stick of ground Artemisia vulgaris—which is also known as mugwort or in Japanese as moxa. At the BL 67 acupuncture point, the stick is directly placed against the skin or indirectly heats an acupuncture needle at the site to increase fetal movement and promote spontaneous breech version. It is performed usually between 33 and 36 weeks’ gestation to permit a trial of external cephalic version if not successful. Results from randomized controlled studies are conflicting. However, a Cochrane Database review found some evidence to support moxibustion use when combined with acupuncture (Cardini, 1998, 2005; Coyle, 2012; Guittier, 2009; Neri, 2004).
Internal Podalic Version
This maneuver is used only for delivery of a second twin. With the membranes preferably still intact, a hand is inserted into the uterine cavity to turn the fetus manually. The operator seizes one or both feet and draws them through the fully dilated cervix, while using the other hand transabdominally to push the upper portion of the fetal body in the opposite direction as shown in Chapter 45 (p. 918). This is then followed by breech extraction.
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