Differences in fetal growth, discordancy, and placental pathology in reduced versus nonreduced twins

This study evaluated the effect of multifetal pregnancy reduction on the incidence of small for gestational age (SGA) and discordance in reduced versus nonreduced twins and differences in placental pathology. A computerized ultrasound database was used to identify diamniotic-dichorionic twins who delivered at our institution. Reduced (n = 36) versus nonreduced twins (n = 243) were compared for differences in rates of SGA and discordancy (>or= 20%.) The groups were compared for differences in maternal and neonatal characteristics, as well as differences in placental pathology. Chi-square tests were used to compare differences in means. Stepwise logistic regression was used to adjust for potential confounders including placental pathology. The rate of SGA in either twin A or B remained nonsignificant after adjustment for the use of assisted reproductive technology and gestational age at delivery in the stepwise logistic model (odds ratio, 1.7 95%; confidence interval, 0.5, 5.2). The average discordance at delivery was 12.4% in reduced versus 11.4% in the nonreduced twins ( P = 0.54). We found no overall differences in placental pathology between the two groups. Reduced and nonreduced twins have no significant differences in SGA fetuses, growth discordancy, or placental pathology.