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:
Spontaneous breech delivery. The fetus is expelled entirely spontaneously without any traction or manipulation other than support of the newborn.
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.
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.
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 (Current Recommendations). 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.
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.
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).
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).
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.
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.
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.
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).
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
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).
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.
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.
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 (Puerperal Hematomas).
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).
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).
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 (Nuchal Arm). 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 (Nuchal Arm). These maneuvers are also used during cesarean delivery of the frank breech through the hysterotomy incision.
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.
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.