FIGURE 28-8 Infrequently, the posterior arm must be delivered first. For this, the lower half of the fetal body is raised up and over the maternal groin. The provider's fingers are inserted under the posterior shoulder and aligned with the humerus. (Reproduced with permission from Yeomans ER: Vaginal breech delivery. In Yeomans ER, Hoffman BL, Gilstrap LC III, et al (eds): Cunningham and Gilstrap's Operative Obstetrics, 3rd ed. New York, McGraw-Hili Education, 2017.) 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.
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 diicult 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 unsuccessul, the nuchal arm oten is extracted by hooking a inger(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.
Delivery of the Aftercoming Head
Mauriceau Maneuver. 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.
With the Mauriceau maneuver, the index and middle inger of one hand are applied over the maxilla, to flex the head, while
FIGURE 28-10 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.
FIGURE 28-9 Reduction of a right nuchal arm is accomplished by rotating the fetal body 180 degrees counterclockwise, which directs the fetal back to the maternal right. Friction exerted by the birth canal will draw the elbow toward the face. (Reproduced with permission from Yeomans ER: Vaginal breech delivery. In Yeomans ER, Hoffman BL, Gilstrap LC III, et al (eds): Cunningham and Gilstrap's Operative Obstetrics, 3rd ed. New York, McGraw-Hili Education, 201•7.) the fetal body rests on the palm of the same hand and forearm (Fig. 28-10). Fetal legs straddle the forearm. Two ingers 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.