Rarely, delivery can be obstructed by extreme hydrocephaly, by body stalk anomaly, or by massive fetal abdominal enlargement from a greatly distended bladder, ascites, or organomegaly (Costa, 2012; Sikka, 2011). With milder forms of hydrocephaly, if the biparietal diameter is < 10 cm or if the head circumference is <36 cm, then vaginal delivery may be permitted (Anteby, 2003).
FIGURE 27-9 Deinfibulation. Although not shown here, lidocaine is first infiltrated along the planned incision if regional analgesia is not in place already. As protection, two fingers of one hand are insinuated behind the shelf created by fused labia but in front of the urethra and crowning head. The shelf is then incised in the midline. After delivery, the raw edges are sutured with rapidly absorbable material to secure hemostasis. (Reproduced with permission from Hawkins JS: Lower genital tract procedures. In Yeomans ER, Hoffman BL, Gilstrap LC III, et al (eds): Cunningham and Gilstrap's Operative Obstetrics, 3rd ed. New York, McGraw-Hili Education, 201o7.)
In rare cases in which neonatal death has occurred or is certain due to associated anomalies, vaginal delivery may be reasonable, but the head or abdomen must be reduced in size for delivery. Removal of luid by cephalocentesis or paracentesis with sonographic guidance can be performed intrapartum. As described on page 523, cleidotomy can shorten the bisacromial diameter. For hydrocephalic fetuses that are breech, cephalocentesis can be accomplished suprapubically when the aftercoming head enters the pelvis. Currently, these practices are more germane in developing countries.
• Delivery of the Placenta hird-stage labor begins immediately after fetal birth and ends with placental delivery. Goals include delivery of an intact placenta and avoidance of uterine inversion or postpartum hemorrhage. The latter two are grave intrapartum complications and constitute emergencies, as described in Chapter 41 (p. 755).
Immediately after newborn birth, uterine fundal size and consistency are examined. If the uterus remains irm and there is no unusual bleeding, watchful waiting until the placenta separates is the usual practice. Neither massage nor downward fundal pressure is employed, but the fundus is frequently palpated to ensure that it does not become atonic and illed with blood from placental separation. To prevent uterine inversion, umbilical cord traction must not be used to pul the placenta rom the uterus. Signs of separation include a sudden gush of blood into the vagina, a globular and firmer fundus, a lengthening of the umbilical cord as the placenta descends into the vagina, and elevation of the uterus into the abdomen. With the last, the placenta, having separated, passes down into the lower uterine segment and vagina. Here, its bulk pushes the uterine body upward.