Preterm delivery and growth restriction in multifetal pregnancies reduced to twins: Case-control series

Abstract

An adverse consequence of the widespread introduction of assisted reproductive techniques has been an exponential increase in the prevalence of multifetal pregnancies (Botting et al 1987). Such pregnancies are associated with increased risk of miscarriage and perinatal death (Kiely et al 1992). One of the options in the management of multifetal pregnancies is embryo reduction to twins which is associated with a reduction in the background risk of adverse pregnancy outcome (Evans et al 1995). The aim of the study was to compare the gestation at delivery and birth weight of surviving twins following multifetal pregnancy reduction to those in a control group of dichorionic non-reduced twins. Materials and methods: A case control study evaluating pregnancy outcomes post embryo reduction. Study takes into account all patients with successful day three embryo transfers resulting in multifetal pregnancy. First trimester embryo reduction was carried out by intracardiac injection of KCl. Results: A total of 26 multifetal pregnancies were reduced to twins at early gestational age (7-9 weeks). Two cases (7.6%) of miscarriage, no cases of chorioamnionitis and five cases (19.2%) of transient spotting were recorded as postoperative complications. There was no vanishing of embryos in those reduced to twins. A total of 24 patients (92.3%) with twin pregnancies took home at least one baby, while 18 (69.23%) of these took both babies home. This was analyzed and compared with a control group of women with nonreduced twins pregnancies. The preterm delivery rate (defined as fetuses delivered before 37 weeks) in twin pregnancies was 53.8% (n = 14), with a severe preterm rate (defined as fetuses delivered before 32 weeks) of 23.07% (n = 6). One case (1.92%) of stillbirth occurred. The perinatal mortality rate was 13.46% (n = 6 newborns, and a 33-week stillbirth), mainly due to severe preterm labor. The latter group included no registered cases of newborns with congenital malformations. A total of 24 patients (92.3%) with twin pregnancies took home at least one baby, while 18 (69.23%) of these took both babies home. In two of the 26 multifetal pregnancies reduced to twins there was miscarriage of both fetuses before 24 weeks of gestation the median interval between reduction and multifetal loss was 5 weeks. In pregnancy reduced to twins as compared to nonreduced twins the percentage of miscarriage was slightly higher, but not statistically significant (7.6% compared to 6.9%, 0.07 × 2, P 0.8). The median gestation at delivery was lower (33.3 ± 9.2 compared to 35.67 ± 5.84 weeks, 2.26 > 2.0 t, 0.05 P) and themedian weight deficit was greater (1.58 ± 0.96 compared to 1.92 ± 0.89 (4.04 > 3.37 t, 0.001 P).