After immature delivery of the first infant in women with multifetal pregnancies, attempts have been made to delay the delivery of remaining twins, triplets, and higher-order multiples to improve perinatal outcome. Survival of over 90% of the remaining multiples was achieved in several case reports but the protocols varied widely. Few prospective studies have been conducted. This prospective study assessed the neonatal outcome and maternal risks for subsequent delivery of twin and triplet pregnancies after immature (<25 weeks) or early premature (25-31 weeks) delivery of the first multiples. Candidates for delayed interval were selected and managed at a single high-risk center using a standard protocol established before enrollment. The study group was comprised of cases in which the first twin or triplet was born vaginally between 16 and 31 weeks of gestation and the delivery of the remaining multiples could be delayed. The investigators collected data between 1991 and 2007 on 93 twins and 34 triplet pregnancies, complicated by threatening early delivery of the first fetus between 16 and 31 gestational weeks.
Forty-five twin and 8 triplet pregnancies were excluded from the analysis because of contraindications to delayed pregnancy. Immediate delivery occurred in 10 of the remaining 48 twins and in 14 of the remaining 26 triplet pregnancies. As a result, the final study population was comprised of 41% (38 of 93) of all twin and 35% (12 of 34) of all triplet pregnancies admitted with threatening birth before 31 weeks. The mean interval between the delivery of the first and second twin was 19 days (range: 1-106 days). For deliveries <25 weeks, no first twin but 50% (9 of 18) of second twins survived (P < 0.001). For deliveries >25 weeks, 65% (13 of 20) of the first twins survived, whereas 95% (19 of 20) of the corresponding second twins survived (P < 0.03). For triplet pregnancies, the mean delay between delivery of the first and the third triplet was 18 days (range: 1-118 days). Of the 12 triplets, 7 firstborns were delivered <25 weeks. None of these first triplets but 2 of the remaining triplets survived after an interval of 118 days. For deliveries >25 weeks, 60% (3 of 5) of the first triplets and 40% (4 of 10) of the remaining triplets survived after a delay of 2 to 13 days. The interval between the delivery of the second and third triplet was ≤2 days. Frequently seen maternal complications included chorioamnionitis (22%), postpartum hemorrhage (10%), retained placenta (10%), and abruption (6%). This is the first prospective and largest 1-center study examining the success rate of attempted asynchronous delivery in twin and triplet pregnancies.