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Vaginal Delivery Methods
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The conduct of both labor and delivery differ between cephalic and breech presentations. First, breech labor in general proceeds more slowly, but steady cervical progress is a positive indicator of adequate pelvic proportions (Lennox, 1998). Vaginal breech delivery is accomplished by one of three methods. With spontaneous breech delivery, the fetus is expelled entirely without any traction or manipulation other than support of the newborn. With partial breech extraction, the fetus is delivered spontaneously as far as the umbilicus, but the remainder of the body is delivered by provider traction and assisted maneuvers, with or without maternal expulsive efforts. With total breech extraction, the entire fetal body is extracted by the provider.
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Labor Induction and Augmentation
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As with many other aspects of breech position, induction or augmentation of labor is controversial. Here again, data are limited and mostly retrospective. With labor induction, Burgos and coworkers (2017) reported equivalent vaginal delivery rates compared with spontaneous labor. With induction, however, they reported higher rates of neonatal intensive care unit admission. But, others have found similar perinatal outcome and cesarean delivery rates (Jarniat, 2017; Marzouk, 2011). Finally, others described greater cesarean delivery rates with induction but similar neonatal outcomes (Macharey, 2016).
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In many studies, successful vaginal delivery is associated with orderly labor progression. Thus, some protocols avoid augmentation for the breech-presenting fetus, 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 pharmacological labor induction or augmentation.
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On arrival to the labor unit, surveillance of fetal heart rate and uterine contractions begins, and immediate recruitment of necessary staff includes: (1) a provider 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, intravenous access is obtained. This allows, if needed, emergency induction of anesthesia or maternal resuscitation following hemorrhage from lacerations or from uterine atony.
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At admission, the status of the membranes and progression of labor are assessed. Knowledge regarding cervical dilatation, cervical effacement, and presenting part station is essential for preparation. If labor is too far advanced, pelvimetry may be unsafe if fetal expulsion in the radiology department is a possibility. This alone, however, should not force the decision for cesarean delivery. As mentioned, stepwise labor progression itself is a good indicator of pelvic adequacy (Biswas, 1993). Sonographic assessment, described earlier, is completed. Ultimately, the choice of abdominal or vaginal delivery is based on factors discussed earlier and listed in Table 28-1.
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During labor, one-on-one nursing is ideal because of cord prolapse risks, and physicians must be readily available for such emergencies. Guidelines for monitoring the high-risk fetus are applied (Chap. 24, Intrapartum Surveillance of Uterine Activity). For first-stage labor, while most clinicians prefer continuous electronic monitoring, the fetal heart rate is recorded at a minimum of every 15 minutes. A scalp electrode can be safely affixed to the buttock, but genitalia are avoided. If a nonreassuring fetal heart rate pattern develops, then a decision must be made regarding the necessity of cesarean delivery.
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When membranes rupture, 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. Therefore, vaginal examination is performed immediately following rupture, and special attention is directed to the fetal heart rate for the first 5 to 10 minutes thereafter.
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For women in labor with a breech presentation, continuous epidural analgesia is advocated by some. This may increase the need for labor augmentation and prolong second-stage labor (Chadha, 1992; Confino, 1985). These potential disadvantages are 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 can provide further relief from pain. If general anesthesia is required, it must be induced quickly.
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Spontaneous Breech Delivery
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Similar to vertex delivery, spontaneous expulsion of a breech fetus entails sequential cardinal movements. First, 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.
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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 fetus to straighten out when the anterior hip is born (Fig. 28-4). The legs and feet follow the breech and may be born spontaneously or require aid.
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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 to bring the posterior portion of the neck under the symphysis pubis. The head is then born in flexion.
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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 renders the back of the fetus to lie posteriorly instead of anteriorly. Such rotation is prevented if possible. Although the head can 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.
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Partial Breech Extraction
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With breech delivery, successively larger and less compressible parts are born. Thus, spontaneous expulsion is the exception, and vaginal delivery typically requires skilled provider participation for the fetus to navigate the birth canal. Noteworthy clinical pearls are provided by Yeomans (2017) in the third edition of Cunningham and Gilstrap’s Operative Obstetrics.
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First, with all breech deliveries, unless the perineum is considerably lax, an episiotomy is made and is an important adjunct to delivery. As discussed in Chapter 27 (Episiotomy), mediolateral episiotomy may be preferred for its lower associated risk of anal sphincter lacerations. Ideally, the breech is allowed to deliver spontaneously to the umbilicus. Delivery of the breech draws the umbilicus and attached cord into the pelvis. Therefore, once the breech has passed beyond the vaginal introitus, the abdomen, thorax, arms, and head must be delivered promptly either spontaneously or assisted.
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The posterior hip will deliver, usually from the 6 o’clock position, and often with sufficient pressure to evoke passage of thick meconium (see Fig. 28-4). The anterior hip then delivers, followed by external rotation to a sacrum anterior position. The mother is encouraged to continue to push as the fetus descends until the legs are accessible. The legs are sequentially delivered by splinting the femur with the operator’s fingers positioned parallel to the long axis of the femur, and by exerting pressure upward and laterally to sweep each leg away from the midline (Fig. 28-5).
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Following delivery of the legs, the fetal bony pelvis is grasped with both hands. The fingers should rest on the anterior superior iliac crests and the thumbs on the sacrum. This minimizes the chance of fetal abdominal soft-tissue injury (Fig. 28-6). Maternal expulsive efforts are again used in conjunction with downward traction to affect delivery.
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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. It makes little difference which shoulder is delivered first, and two methods are suitable for their delivery. In the first method, with the scapulas visible, the trunk is rotated either clockwise or counterclockwise to bring the anterior shoulder and arm into view (Fig. 28-7). During delivery of the arm, fingers and hand are aligned parallel to the humerus and act to splint and prevent humeral fracture. The body of the fetus is then rotated 180 degrees in the reverse direction to bring the other shoulder and arm into position for delivery.
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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 (Fig. 28-8). The hand enters over the shoulder, fingers are aligned parallel to the long axis of the humerus, and the fetal arm is swept upward. The posterior shoulder slides out over the perineal margin and is 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. After both shoulders are delivered, the back of the fetus tends to rotate spontaneously to the symphysis. Delivery of the head may then be accomplished.
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During delivery, one or both fetal arms occasionally may lie across the back of the neck and become impacted at the pelvic inlet. With such a nuchal arm, delivery is more difficult and can be aided by rotating the fetus through a half circle in such a direction that the friction exerted by the birth canal will draw the elbow toward the face (Fig. 28-9). With a right nuchal arm, the body should be rotated counterclockwise, which rotates the fetal back toward the maternal right. With a left nuchal arm, the rotation is clockwise. If rotation fails to free the nuchal arm, it may be necessary to push the fetus upward to a roomier part of the pelvis. 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.
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Delivery of the Aftercoming Head
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The fetal head is normally extracted with forceps or by one of several maneuvers. With any of these techniques, hyperextension of the fetal neck is avoided.
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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 same hand and forearm (Fig. 28-10). Fetal legs straddle the forearm. Two fingers of the other hand then are hooked over the fetal neck and grasp 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 slightly elevated toward the maternal abdomen, and the mouth, nose, brow, and eventually the occiput emerge successively over the perineum. With this maneuver, the provider uses both hands simultaneously to exert continuous downward gentle traction while balancing forces between the fetal neck and maxilla to avoid neck hyperextension.
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Specialized forceps can be used to deliver the aftercoming head. Piper forceps, shown in Figure 28-11, or Laufe-Piper forceps may be applied electively or when the Mauriceau maneuver cannot be accomplished easily. The blades of the forceps are not 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.
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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 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 provider’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.
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Once in place, the blades are articulated, and the fetal body rests across the shanks. The head is delivered by pulling gently outward and slightly 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 neck hyperextension.
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Modified Prague Maneuver
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Rarely, the back of the fetus fails to rotate to the symphysis. The fetus still may be delivered using the modified Prague maneuver. With this, two fingers of one hand grasp the shoulders of the back-down fetus from below while the other hand draws the feet up and over the maternal abdomen (Fig. 28-12).
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This emergency reflects either an incompletely dilated cervix or cephalopelvic disproportion. First, especially with a small preterm fetus, an incompletely dilated cervix can constrict around the neck and impede delivery of the aftercoming head. At this point, significant cord compression must be assumed, and time management is essential. With gentle traction on the fetal body, the cervix, at times, may be manually slipped over the occiput. If unsuccessful, then Dührssen incisions may be necessary (Fig. 28-13). General anesthesia with halogenated agents or intravenous nitroglycerin is another option to aid lower uterine segment relaxation. As an extreme measure, replacement of the fetus higher into the vagina and uterus, followed by cesarean delivery, can rescue an entrapped breech fetus. This Zavanelli maneuver is classically performed to relieve intractable shoulder dystocia (Sandberg, 1988). However, case reports also have described its use for an entrapped aftercoming head (Sandberg, 1999; Steyn, 1994).
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In cases with cephalopelvic disproportion and arrest of aftercoming head, the Zavanelli maneuver or symphysiotomy are options (Sunday-Adeoye, 2004; Wery, 2013). Using local analgesia, symphysiotomy 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 provider training and potentially serious maternal pelvic or urinary tract injury explain its rare use in the United States. That said, if cesarean delivery is not possible, symphysiotomy may be lifesaving for both mother and baby (Hofmeyr, 2012).
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Total Breech Extraction
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Complete or Incomplete Breech
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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 middle finger lying between them. With gentle traction, the feet are brought through the introitus (Fig. 28-14). 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. The thumbs are then placed over the sacrum and the fingers over the iliac crests. Breech extraction is then completed, as described for partial breech extraction (Partial Breech Extraction).
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If only one foot can be grasped, it can be brought down into the vagina and held with the appropriate hand, right hand for right foot and left hand for left foot (Yeomans, 2017). With the first foot secure, the opposite hand is introduced, passed upward along the leg, and guided to locate the other foot. If the remaining hip is extended, the second foot is usually easily grasped and brought down. If the hip is flexed and knee extended, a finger is hooked into that groin, and traction will bring the lower half of the fetus down until the leg can be reached. For cesarean delivery, these total breech extraction maneuvers can be used to deliver a complete, incomplete, or footling breech through the hysterotomy incision.
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During complete extraction of a frank breech, moderate traction is exerted by a finger in each groin and aided by a generous episiotomy. Once the breech is pulled through the introitus, the steps described for partial breech extraction are then completed (Partial Breech Extraction). These maneuvers are also used during cesarean delivery of a frank breech through a hysterotomy incision.
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Rarely during vaginal delivery, a frank breech will require decomposition inside the uterine cavity. Attributed to Pinard (1889), this procedure converts a frank breech into a footling breech. It is accomplished more readily if the membranes have ruptured only recently. It becomes extremely difficult if amnionic fluid is scant and the uterus is tightly contracted around the fetus. Pharmacological relaxation by general anesthesia or intravenous magnesium sulfate, nitroglycerin, or a betamimetic agent may be required. To begin, two fingers are carried up along one leg to externally rotate the hip by pressing on the medial side of the thigh parallel to the femur. Simultaneously, pressure in the popliteal fossa should prompt spontaneous knee flexion, which brings the corresponding foot into contact with the back of the provider’s hand. The fetal foot then may be grasped and brought down.