133: Pregnancy outcome after multifetal pregnancy reduction of triplets to twins versus reduction to singleton

Abstract

Multifetal pregnancy reduction (MPR) of triplets to twins results in improved pregnancy outcome compared with triplet gestations managed expectantly. However, it is not clear whether reduction to singleton may further improve pregnancy outcome. The aim of this study was to determine the rate of pregnancy complications and perinatal outcomes of MPR from triplets to twins versus reduction from triplets to singleton 268 trichorionic and dichorionic triplet pregnancies underwent abdominal MPR at 11-14 weeks' gestation. Cases were divided into two groups according to the final number of embryos: group A, reduction to twins (n=221) and group B, reduction to singleton (n=47). Main outcome measures were rates of pregnancy complications, late abortions, preterm delivery and neonatal outcomes. Non-parametric statistical methods were employed. Triplet pregnancies reduced to twins (group A) delivered earlier (36 vs. 38.6 weeks’ gestation, P<0.001) with lower median birth weight (2172g vs. 2820g, P<0.001) compared with triplets reduced to singleton (group B). The rate of preterm delivery prior to 37 weeks was significantly higher in group A compared with group B (61.2% vs. 21.9%, p<0.001), although twins were not more likely to be delivered prior to 34 weeks (20.1% vs. 14.3%, p=0.52). Regression analysis revealed that after adjustment for age, parity, BMI and gestational age at reduction, triplets reduced to singleton had lower risk for preterm delivery (OR=0.14; 95% CI 0.05-0.39, p<0.001). We did not find a significant difference in the rate of pregnancy loss before 24 weeks’ gestation (6.4% vs. 1.4%, p=0.07) or the rate of intrauterine fetal death after 24 weeks (4.3% vs. 0.9%, p=0.15). There was no significant difference in the prevalence of gestational diabetes, hypertensive diseases of pregnancy and intrauterine growth restriction. Both groups had comparable neonatal outcomes, except for higher rates of NICU admission (29.2% vs. 4.5%, p<0.001), oxygen support (8.2% vs. 0%, p=0.05) and neonatal hypoglycemia (13.2% vs. 0%, p=0.04) in group A. Reduction of triplet pregnancies to singleton is associated with a lower risk of prematurity and superior perinatal outcome compared with reduction to twins. Therefore, the option of reduction to singleton should be considered in cases where the risk of prematurity seems exceptionally high.