If asynchronous birth is attempted, there must be careful evaluation for infection, abruption, and congenital anomalies. The mother must be thoroughly counseled, particularly regarding the potential for serious, life-threatening infection. The range of gestational age in which the beneits outweigh the risks for delayed delivery is likely narrow. Avoidance of delivery from 23 to 26 weeks would seem most beneficial. In our experience, good candidates for delayed delivery are rare.
A litany of complications may be encountered during labor and delivery of multiple fetuses. In addition to preterm birth, rates of uterine contractile dysfunction, abnormal fetal presentation, umbilical cord prolapse, placenta previa, placental abruption, emergent operative delivery, and postpartum hemorrhage from uterine atony are higher. All of these must be anticipated, and thus certain precautions and special arrangements are prudent. These should include the following.
1.
An appropriately trained obstetrical attendant should remain with the mother throughout labor. Continuous electronic monitoring is preferable. If membranes are ruptured and the cervix dilated, the presenting fetus is monitored internally.
2.
An intravenous infusion system capable of delivering fluid rapidly is established. In the absence of hemorrhage, lactated Ringer or an aqueous dextrose solution is infused at a rate of 60 to 125 mLlhr.
3.
Blood for transfusion is readily available if needed.
4.
n obstetrician skilled in intrauterine identification of fetal parts and in intrauterine manipulation of a fetus should be present.
5.
A sonography machine is readily available to evaluate the presentation and position of the fetuses during labor and to image the remaining fetus(es) after delivery of the irst.
6.
An anesthesia team is immediately available in the event that emergent cesarean delivery is necessary or that intrauterine manipulation is required for vaginal delivery.
7.
For each fetus, at least one attendant who is skilled in resuscitation and care of newborns and who has been appropriately informed of the case should be immediately available.
8.
he delivery area should provide adequate space for the nursing, obstetrical, anesthesia, and pediatric team members to work efectively. Equipment must be on site to provide emergent anesthesia, operative intervention, and maternal and neonatal resuscitation.
• Timing of Delivery
Several factors afect this timing and include gestational age, fetal growth, lung maturity, and presence of maternal complications. As measured by determination of the lecithin-sphingomyelin ratio, pulmonary maturation is usually synchronous in twins (Leveno, 1984). Moreover, although this ratio usually does not exceed 2.0 until 36 weeks in singleton pregnancies, it oten exceeds this value by approximately 32 weeks in multifetal pregnancies. Similar increased values of surfactant have been noted in twins after 31 weeks' gestation (McElrath, 2000). In a comparison of respiratory morbidity in 100 twins and 241 singleton newborns delivered by cesarean before labor, Ghi and associates (2013) found less neonatal respiratory morbidity in twins, especially those delivered <37 weeks' gestation. In some cases, however, pulmonary function may be markedly diferent, and the smallest, most stressed twin fetus is typically more mature.
At the other end of the spectrum, Bennett and Dunn (1969) suggested that a twin pregnancy of 40 weeks or more should be considered postterm. Twin stillborn neonates delivered at 40 weeks or beyond commonly had features similar to those of postmature singletons (Chap. 43, p. 836). From an analysis of almost 300,000 twin births, at and beyond 39 weeks, the risk of subsequent stillbirth was greater than the risk of neonatal mortality (Kahn, 2003).