Outcome of twin pregnancies reduced from triplets compared with nonreduced twin gestations

To compare the outcome of triplet pregnancies reduced to twins who reached 24 weeks' gestation with the outcome of twin pregnancies managed in the same perinatal department.

The study group included 43 triplet pregnancies reduced to twins who reached 24 weeks' gestation and were delivered between January 1989 and December 1993. The complications and outcomes of these pregnancies were compared with all 134 bichorionic twin pregnancies delivered during 1993.

In general, the outcome of triplet pregnancies reduced to twins was not significantly different from that of twin pregnancies. Both pregnancy-induced hypertension and premature contractions were similar in the two groups. The higher incidence of premature rupture of membranes (PROM) in the reduced cases compared with nonintervention twins (18.6 versus 8.2%) was of borderline significance (relative risk [RR] 2.27, 95% confidence interval [CI] 0.98-5.27). Although premature delivery occurred in 30% of patients in both groups, 20.9% of patients in the reduction group delivered before 35 weeks' gestation, compared with 10.4% in the nonintervention group (RR 2.0, 95% CI 0.93-4.30). The mean gestational age was similar in the two groups, as was the risk of low birth weight and respiratory disorders. Differences in the proportion of patients with PROM, low gestation duration, and very low birth weight, although not quite statistically significant, are probably because of the relatively small numbers and, hence, of low power (50-55%), but may be of clinical importance.

The outcome of triplet pregnancies reduced to twins did not differ substantially from that of nonreduced twin pregnancies.