Breech presentation at the onset of labor occurs in 3 to 4 percent of all singleton deliveries. Ultrasound ideally can be used to confirm a clinically suspected breech presentation as well as diagnose fetal or uterine anomalies. In a persistent breech presentation, both mother and fetus are at considerable risk compared with a woman with a cephalic presentation. These complications are listed in Table 17-1.
TABLE 17-1. Some Maternal and Fetal Complications Associated with Breech Presentation
Frank breech presentation is diagnosed when the lower extremities are flexed at the hips and extended at the knees, with the feet lying in close proximity to the head (Figure 17-1). A complete breechpresentation differs in that one or both knees are flexed (Figure 17-2). With incomplete breech presentation (Figure 17-3), one or both hips are not flexed and one or both feet or knees lie below the breech, that is, a foot or knee is lowermost in the birth canal.
FIGURE 17-1 Frank breech presentation. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
FIGURE 17-2 Complete breech presentation. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
FIGURE 17-3 Incomplete breech presentation. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
The route of delivery of a fetus presenting breech remains controversial. The number of skilled operators able to safely deliver breech fetuses continues to dwindle and resident training has decreased. In the United States, most breech presentations are now delivered by cesarean section. The American College of Obstetricians and Gynecologists (Mode of term singleton breech delivery, Committee Opinion No. 265, December 2001) has made the following statement concerning delivery of singleton breech presentations at term:
In those instances in which breech vaginal deliveries are pursued, great caution should be exercised. Patients with a persistent breech presentation at term in a singleton gestation should undergo a planned cesarean delivery. If the patient refuses a planned cesarean delivery, informed consent should be obtained and should be documented. A planned cesarean delivery does not apply to patients presenting in advanced labor with a fetus in the breech presentation in whom delivery is likely to be imminent or to patients whose second twin is in a nonvertex presentation.
In this chapter, we will describe the techniques for vaginal delivery of singleton frank breech presentation should such be required. The techniques for vaginal delivery of complete and incomplete breeches are described in detail in Chapter 24 of Williams Obstetrics, 23rd edition. The technique for external cephalic version of breech presentation to cephalic is provided at the end of this chapter.
TECHNIQUE FOR VAGINAL DELIVERY OF FRANK BREECH PRESENTATIONS
A rapid assessment should be made to establish the status of the fetal membranes, labor, and condition of the fetus. Close surveillance of fetal heart rate and uterine contractions should begin. An immediate recruitment of the necessary nursing and medical personnel to accomplish a vaginal or abdominal delivery should also be done. Included are nursery and anesthesia personnel. An intravenous infusion through a venous catheter is begun as soon as the woman arrives in the labor suite.
Assessment of cervical dilatation and effacement and the station of the presenting part are essential in planning the route of delivery. The presence or absence of gross fetal abnormalities, such as hydrocephaly or anencephaly, can be rapidly ascertained with the use of sonography. Such efforts will help ensure that a cesarean delivery is not done under emergency conditions for an anomalous infant with no chance of survival. If vaginal delivery is planned, the fetal head should not be extended. It is possible to ascertain head flexion and to exclude extension using sonography. Many clinicians recommend using computed tomographic pelvimetry to assess pelvic capacity.
Delivery is easier, and in turn, morbidity and mortality rates are probably lower, when the breech is allowed to deliver spontaneously to the umbilicus. Delivery of the breech draws the umbilicus and attached cord into the pelvis, which compresses the cord. Therefore, once the breech has passed beyond the vaginal introitus, the abdomen, thorax, arms, and head must be delivered promptly. If a nonreassuring fetal heart rate pattern develops before this time, however, a decision must be made whether to perform manual extraction or cesarean delivery.
With all breech deliveries, unless there is considerable relaxation of the perineum, an episiotomy should be made. The episiotomy is an important adjunct to any type of breech delivery. The posterior hip will deliver, usually from the 6 o’clock position, and often with sufficient pressure to evoke passage of thick meconium at this point (Figure 17-4). 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 cord is now drawn well down into the birth canal and likely is being compressed or stretched causing fetal bradycardia. 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 17-4 The hips of the frank breech are delivering over the perineum. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
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 (Figure 17-5). Maternal expulsive efforts are used in conjunction with continued gentle downward operator rotational traction to affect delivery. Gentle downward traction is combined with an initial 90-degree rotation of the fetal pelvis through one arc and then a 180-degree rotation to the other, to effect delivery of the scapulas and arms (Figures 17-6 and 17-7).
FIGURE 17-5 The anterior hip has now delivered and external rotation has occurred. The fetal thighs remain in flexion with extension at the knees.
FIGURE 17-6 Delivery of the body. The hands are applied, but not above the pelvic girdle. Gentle downward rotational traction is accomplished until the scapulas are clearly visible. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
FIGURE 17-7 Clockwise rotation of the fetal pelvis 180 degrees brings the sacrum from anterior to left sacrum transverse. Simultaneously, exerting gentle downward traction affects delivery to the scapula (A) and arm (B–D). (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
These rotational and downward traction maneuvers will decrease the persistence of nuchal arms, which can prevent further descent and may result in a traumatic delivery. These maneuvers are frequently most easily affected with the operator at the level of the maternal pelvis and with one knee on the floor. When the scapulas are clearly visible, delivery is then completed as subsequently described for the complete or incomplete breech.
Management of Nuchal Arms
As discussed earlier, one or both fetal arms occasionally are found around the back of the neck (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 described, extraction may be facilitated, especially with a single nuchal arm, by rotating the fetus through half a circle in such a direction that the friction exerted by the birth canal will serve to draw the elbow toward the face (Figure 17-8). 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 is often 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 very common.
FIGURE 17-8 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. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
The fetal head may then be extracted with forceps or by one of the following maneuvers.
The index and middle finger of one hand are applied over the maxilla, to flex the head, while the fetal body rests upon the palm of the hand and forearm (Figure 17-9). The 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 applied until the suboccipital region appears under the symphysis. Gentle suprapubic pressure simultaneously applied by an assistant helps keep the head flexed. The body of the fetus is then elevated toward the maternal abdomen, and the mouth, nose, brow, and eventually the occiput emerge successively over the perineum. It is emphasized that with this maneuver the operator uses both hands simultaneously and in tandem to exert continuous downward gentle traction bilaterally on the fetal neck and on the maxilla. At the same time, appropriate suprapubic pressure applied by an assistant is helpful in delivery of the head.
FIGURE 17-9 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. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
Forceps to Aftercoming Head
Specialized forceps can be used to deliver the aftercoming head of the breech-presenting fetus. Piper forceps, shown in Figure 17-10, 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 helps keep the arms out of the way.
FIGURE 17-10 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 applied to the aftercoming head. B. The right blade is applied with the body still elevated. C. Forceps delivery of aftercoming head. Note the direction of movement shown by the arrow. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
Entrapment of the Aftercoming Head
Occasionally, especially with small preterm fetuses, the incompletely dilated cervix will not allow delivery of the aftercoming head. With gentle traction on the fetal body, the cervix, at times, may be manually slipped over the occiput. If these actions are not rapidly successful, Dührssen incisions (Figure 17-11) can be made in the cervix. Replacement of the fetus higher into the vagina and uterus, followed by cesarean delivery, can be used successfully to rescue an entrapped breech that cannot be delivered vaginally.
FIGURE 17-11 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. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
Frank Breech Extraction
At times, extraction of a frank breech may be required and can be accomplished by moderate traction exerted by a finger in each groin and facilitated by a generous episiotomy. If moderate traction does not affect delivery of the breech, then vaginal delivery can be accomplished only by breech decomposition. This procedure involves intrauterine manipulation to convert the frank breech into a footling breech. The procedure is accomplished more readily if the membranes have ruptured recently, and it becomes extremely difficult if considerable time has elapsed since escape of amnionic fluid. In such cases, the uterus may have become tightly contracted over the fetus, and pharmacological relaxation by general anesthesia, intravenous magnesium sulfate, or small doses of nitroglycerin, (50 to 100 μg) or a β-mimetic such as terbutaline (250 μg) may be required.
Breech decomposition is accomplished by the maneuver attributed to Pinard. It aids in bringing the fetal feet within reach of the operator. As shown in Figure 17-12, 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 upon the back of the hand. The fetal foot then may be grasped and brought down.
FIGURE 17-12 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. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
Analgesia and Anesthesia for Labor and Delivery
Analgesia for episiotomy and intravaginal manipulations that are needed for breech extraction can usually be accomplished with epidural pudendal block, or local infiltration of the perineum. Nitrous oxide plus oxygen inhalation provides further relief from pain. If general anesthesia is required, it can be induced quickly with thiopental plus a muscle relaxant and maintained with nitrous oxide. Anesthesia for intrauterine manipulation and breech extraction must provide sufficient relaxation. Epidural or spinal analgesia may prove effective although increased uterine tone may render the intrauterine operation more difficult. Under such conditions, one of the halogenated anesthetic agents may be required to relax the uterus as well as provide analgesia.
VERSION OF THE BREECH FETUS
Version is a procedure in which the presentation of the fetus is altered artificially, 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. In external version, the manipulations are performed exclusively through the abdominal wall; while in internal version, the entire hand is introduced into the uterine cavity.
External Cephalic Version
External version of breech presentation to cephalic is successful in 60 percent of cases. If version succeeds, almost all fetuses stay cephalic. If a breech or transverse lie is diagnosed in the last weeks of pregnancy, its conversion to cephalic may be attempted, provided that there is no marked disproportion between the size of the fetus and the pelvis, and provided there is no placenta previa. The most consistent factor associated with success is parity, followed by fetal presentation and then the amount of amnionic fluid. Gestational age is also important—the earlier a version is performed, the more likely it is to be successful. Predictors of failed version include engaged presenting part, difficulty palpating the fetal head, and a tense uterus.
External cephalic version should be carried out in an area equipped to perform emergency cesarean deliveries. Real-time ultrasonic examination is performed to confirm noncephalic term presentation, adequacy of amnionic fluid volume (vertical pocket of 2 cm or greater), and estimated fetal weight; rule out obvious fetal anomalies; and identify placental location. External monitoring is performed to assess fetal heart rate reactivity. A “forward roll” of the fetus is usually attempted first and the “back flip” technique is then tried if unsuccessful. Each hand grasps one of the fetal poles as shown in Table 17-2 and Figure 17-13. The fetal buttocks are elevated from the maternal pelvis, and displaced laterally. The buttocks are then gently guided toward the fundus, while the head is directed toward the pelvis. Version attempts are discontinued for excessive discomfort, persistently abnormal fetal heart rate, or after multiple failed attempts. D-immune globulin is given to D-negative, unsensitized women.
TABLE 17-2. Factors That May Modify the Success of External Cephalic Version
FIGURE 17-13 External cephalic version. A. Clockwise pressure is exerted against the fetal poles. B. Successful completion is noted by feeling the head above the symphysis during Leopold examination. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
Uterine relaxation with a tocolytic agent, usually terbutaline 0.25 mg may be given subcutaneously. There is not enough consistent evidence to recommend regional analgesia, according to the American College of Obstetricians and Gynecologists (External cephalic version, Practice Bulletin No. 13, February 2000).
Risks of external version include placental abruption, uterine rupture, amnionic fluid embolism, fetomaternal hemorrhage, isoimmunization, preterm labor, fetal distress, and fetal demise. There have been no reported fetal deaths in the United States resulting directly from external version since 1980. Reported nonfatal complications include fetal heart rate decelerations in almost 40 percent of fetuses and fetomaternal hemorrhage in 4 percent.
Internal Podalic Version
This maneuver consists of turning the cephalic presenting fetus by inserting a hand into the uterine cavity, seizing one or both feet, and drawing them through the cervix while pushing transabdominally the upper portion of the fetal body in the opposite direction (Figure 17-14). The operation is followed by breech extraction. There are very few, if any, indications for internal podalic version other than for delivery of a second twin (see Chapter 40).
FIGURE 17-14 Internal podalic version. Upward pressure of the head by an abdominal hand is applied as downward traction is exerted on the feet. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)
For further reading in Williams Obstetrics, 23rd ed.,
see Chapter 24, “Breech Presentation and Delivery.”