In approximately 2 percent of singleton births, the placenta may not deliver promptly (Cheung, 2011). Three possibilities include pacenta adherens, in which uterine contractions are insu.cient to detach the placenta; lower uterine segment constriction and a detached but trapped placenta; or a morbidly adherent placenta. Consistent risks for retained placenta include stillbirth, prior cesarean delivery, prior retention, and preterm delivery (Belachew, 2014; Coviello, 2015; Endler, 2014; Nikolajsen, 2013). For the last, in one study with nearly 46,000 deliveries, analysis predicted that 90 percent of placentas would spontaneously deliver by 180 minutes for gestations at 20 weeks; 21 minutes at 30 weeks; and 14 minutes at 40 weeks (Dombrowski, 1995).
Postpartum hemorrhage can complicate a retained placenta, and bleeding risk accrues with third-stage length. Thus, in the absence of bleeding, some recommend expectant management for 30 minutes, whereas others use a 15-minute threshold (Cummings, 2016; Deneux-Tharaux, 2009; Shinar, 2016a). he World Health Organization (2012) cites a 60-minute threshold. Notably, if brisk bleeding ensues and the placenta cannot be delivered by standard technique, manual removal of the placenta is indicated (Fig. 27-12). When performed, some administer a single dose of intravenous antibiotics, however, one systematic review of observational studies found no beneits (Chibueze, 2015). Although the American College of Obstetricians and Gynecologists (2016c) concludes that data neither support nor refute this practice, the World Health Organization (2012) recommends prophylaxis. At our institution, we administer a single dose to women not already receiving antibiotics.
The hour immediately following delivery of the placenta is critical. During this time, lacerations are repaired. Although utero tonics are administered, postpartum hemorrhage as the result of uterine atony is most likely at this time. Hematomas may expand. Consequently, uterine tone and the perineum are frequently evaluated. The American Academy of Pediatrics and the American College of Obstetricians and Gynecologists (20 17b) recommend that maternal blood pressure and pulse be recorded immediately after delivery and every 15 minutes for the first 2 hours. The placenta, membranes, and umbilical cord are examined for completeness and for anomalies, as described in Chapter 6 (p. 111).
Lower genital tract lacerations may involve the cervix, vagina, or perineum. Those of the cervix and vagina are described in Chapter 41 (p. 763). Those of the perineum oten follow vaginal delivery, and most are irst-and second-degree lacerations. Lacerations are classified by their depth, and complete deinitions and visual examples are given in Figure 27-13. Of these, third-degree lacerations relect anal sphincter injury and are now subcategorized as: (3c) EAS plus internal anal sphincter (lAS) tears.
FIGURE 27-12 Manual removal of placenta. A. One hand grasps the fundus and the other hand is inserted into the uterine cavity and the fingers are swept from side to side as they are advanced. B. When the placenta detaches, it is grasped and removed.