Multifetal pregnancies are often complicated by spontaneous preterm delivery, thereby placing the neonates at risk for prolonged hospitalization, serious morbidity, and mortality. Typically, all fetuses of a multiple gestation deliver within a short interval; however, in selected cases, the preterm birth of one fetus may not require delivery of the other fetus(es). An extended time interval between births of siblings at a critical gestational age may improve neonatal survival and reduce morbidity from preterm birth.
This topic will discuss selection of candidates for delayed-interval delivery and management of these pregnancies. Interpretation of available information is challenging because the evidence base consists of case reports, small case series, and literature reviews, but no randomized trials. Ascertainment bias is a significant problem as successful outcomes often are reported, while many unsuccessful cases go unreported.
APPROPRIATE CANDIDATES FOR DELAYED-INTERVAL DELIVERY
We discuss the option of delayed-interval delivery with patients when delivery of some fetuses of a multiple gestation is indicated because of maternal, obstetrical, or fetal factors and concurrent delivery of fetuses unaffected by these factors would likely result in their death or severe morbidity. This is a rare event and a complex clinical decision as it is difficult to objectively quantify and compare the potential risks and benefits for the various stakeholders. There are no high-quality data on which to select or exclude candidates for delayed-interval delivery and no generally accepted, published guidelines for selection of appropriate pregnancies.
We believe the best candidates for delayed-interval delivery are pregnancies at an early gestational age (<24 weeks) in which only the first (presenting) fetus spontaneously delivers due to preterm labor, cervical insufficiency, premature rupture of membranes, or intrauterine demise.
We do not offer delayed-interval delivery to women with pregnancies ≥28 weeks of gestation because neonatal outcome at our institution is generally good at this gestational age. We also avoid delayed-interval delivery in women with pregnancy complications associated with a high risk of serious maternal or fetal morbidity/mortality in ongoing pregnancies, such as severe preeclampsia, abruptio placentae, and intraamniotic infection of the nonpresenting fetus(es). In our practice, the finding of intraamniotic infection involving the first fetus or the requirement for oxytocin augmentation to facilitate its delivery does not exclude the woman as a candidate for a delayed-interval delivery; however, evidence of intraamniotic infection (by amniocentesis) of the retained siblings would be a contraindication to this approach and would require delivery of the entire pregnancy.