Abstract: Objective To explore the effects of different number of fetal reduction in early pregnancy on perinatal mothers and infants after triplet pregnancy in embryo transfer. Methods The clinical data of 282 cycles of triplet pregnancy with fetal reduction after embryo transfer were retrospectively analyzed. According to the keeping number of fetus, the reduction group was divided into singleton group with 28 cycles and twin group with 254 cycles. The subjects of single or twin pregnancy who did not reduce the fetus after embryo transfer were matched with propensity score matching(PSM)and 846 cycles were enrolled as the control group, including 84 cycles in the singleton control group and 762 cycles in the twin control group. The general information, pregnancy outcomes, neonatal weight and perinatal complications of the 4 groups were compared, and Logistic regression was used to make further sensitivity analysis. Results (1)Compared with the control group, the reduction group had higher abortion rate, late abortion rate and perinatal complications rate(P<0.01); shorter gestational weeks(P=0.01); lower full-term birth weight(P<0.01), full-term birth rate(P=0.016), and cesarean section rate(P=0.037). (2)Compared with the twin group, the singleton group had lower cesarean section rate(P=0.001), longer gestational weeks(P<0.01), and higher full-term birth weight(P<0.01). Compared with the twin control group, the singleton control group had higher abortion rate, early abortion birth rate, full-term birth weight and premature birth weight(P<0.01), but lower preterm birth rate(P<0.01). Conclusion Fetal reduction in early pregnancy dose not increase premature birth rate or birth defect rate. However, it does increase abortion rate, risk of perinatal complications and low birth weight. The pregnancy outcome is better in patients with reduction of triplets to singletons than in those to twins.

Key words: Multifetal pregnancy, Fetal reduction, Assisted reproductive technology, Embryo transfer, Clinical outcome