Obstetrical outcomes of embryo reduction and fetal reduction compared to non-reduced twin pregnancies

To prevent perinatal morbidity and mortality of high-order multiple pregnancy (HOMP), multifetal pregnancy reduction (MPR) is offered to some patients. In this study, we investigated whether twin pregnancies derived from MPRs carry a higher adverse obstetrical outcome compared to non-reduced control group of twins.

We retrospectively analyzed the data from HOMPs on which transvaginal ER (n = 153) at a mean gestational age of 7.6 weeks or transabdominal FR (n = 59) at a mean gestational age of 12.4 weeks was performed between December 2006 and January 2018. The risk of each procedure was evaluated by comparing obstetrical outcome with that of a control population of 157 non-reduced twins conceived by infertility treatment.

The mean gestational ages at delivery were 35.2 weeks in the ER group, 35.7 weeks in the FR group, and 34.1 weeks in the control group (P = NS). Compared with those in the control group, the ER group had higher miscarriage (1.3% vs. 6.5%; P = 0.047; OR 0.21; 95% CI 0.45-0.898) and higher overall fetal loss (3.8% vs. 14.4%; P = 0.003; OR 0.24; 95% CI 0.09-0.60) rates. Differently compared with those in the control group, the FR group had no statistical difference in miscarriage (2.5% vs. 1.7%; P=NS) and overall fetal loss (3.8% vs. 6.8%; P=NS) rates.

Compared with the control group, ER in twins had a higher miscarriage and fetal loss rate, whereas FR in twins was similar to the control group. So, the FR procedure is overall a better and safer approach of MPR in reducing morbidity and mortality in HOMPs.