During labor and delivery of multiple fetuses, decisions regarding analgesia and anesthesia may be complicated by problems imposed by preterm labor, preeclampsia, desultory labor, need for intrauterine manipulation, and postpartum uterine atony and hemorrhage.
Labor epidural analgesia is ideal because it provides excellent pain relief and can be rapidly extended cephalad if internal podalic version or cesarean delivery is required. If general anesthesia becomes necessary for intrauterine manipulation, uterine relxation can be accomplished rapidly with one of the halogenated inhalation agents discussed in Chapter 25 (p. 499). Some clinicians use intravenous or sublingual nitroglycerin or intravenous terbutaline to achieve uterine relaxation yet avoid the risks associated with general anesthetics. hese agents are usually best administered by the anesthesia team.
Regardless of fetal presentation during labor, obstetricians must be ready to deal with any change of fetal position during delivery. This is especially true following delivery of the first twin. Importantly, related to delivery method, second twins at term have worse composite neonatal outcomes compared with outcomes of their cotwin regardless of delivery method (Muleba, 2005; Smith, 2007; Thorngren-Jerneck, 2001).
If the first twin presents cephalic, delivery can usually be accomplished spontaneously or with forceps. According to D'Alton (2010), there is general consensus that a trial oflabor is reasonable in women with cephalic-cephalic twins. From their review, Hogle and associates (2003) found that planned cesarean delivery does not improve neonatal outcome when both twins are cephalic. The randomized trial by Barrett and coworkers (2013) airms this conclusion.
The optimal delivery route for cephalic-noncephalic twin pairs remains controversial. Patient selection is crucial, and options include cesarean delivery of both twins, or less commonly, vaginal delivery with intrapartum external cephalic version of the second twin. Longer intertwin delivery time has been shown in some studies to be associated with poorer second twin outcome (Edris, 2006; Stein, 2008). Thus, breech extraction may be preferable to version. Least desirable, vaginal delivery of the first but cesarean delivery of the second twin may be required due to intrapartum complications such as umbilical cord prolapse, placental abruption, contracting cervix, or fetal distress.
·Most but not all studies report the worst composite fetal out comes for this scenario (Alexander, 2008; Rossi, 2011; Wen, 2004).
Several reports attest to the safety of vaginal delivery of second noncephalic twins whose birthweight is > 1500g. A French multicenter study of 5915 twin pregnancies illustrates this (Schmitz, 2017). Of these, 25 percent had a planned cesarean delivery. The other 75 percent with a first twin cephalic and gestational age > 32 weeks had a planned trial of vaginal delivery, which was successful in 80 percent. Interestingly, perinatal mortality and morbidity rates were significantly higher in the planned cesarean delivery group delivered <37 weeks-5.2 versus 3.0 percent, respectively. Fox and colleagues (2014) reported outcomes in 287 diamnionic twin pregnancies, of which 130 underwent a planned vaginal delivery. Only 15 percent of the planned vaginal delivery group underwent a cesarean delivery. Perinatal outcomes were similar in both groups. hese two studies included only those fetuses with estimated weightsr> 1500 g. Notably, comparable or even better fetal outcomes with vaginal delivery have been reported with neonates weighing < 1500 g compared with those weighing > 1500 g (Caukwell, 2002; Davidson, 1992).