Abstract：Objective To evaluate the fetal growth pattern and perinatal outcome after selective feticide of monochorionic diamniotic (MCDA) twin pregnancy. Methods A case-control study was conducted during January 2016 to December 2020 in Peking University Third Hospital. 85 MCDA twin pregnant women with selective feticide were selected as MCDA twin pregnancy with intervention group, 171 singleton pregnant women and 165 MCDA twin pregnant women who did not undergo intervention (MCDA twin pregnancy without intervention group) were matched by general characteristics. The fetal intrauterine development and perinatal outcome of the three groups were analyzed. Results The estimated fetal weight (EFW), abdominal circumstance (AC), femur length(FL), biparietal diameter(BPD) and head circumference(HC) in the singleton control group were higher than those of MCDA groups, only AC in MCDA twin pregnancy with intervention is higher than those without intervention, and there was no significant difference in the other indicators between the twin groups. The cesarean section rate of MCDA twin pregnancy with intervention group was significantly lower (52.9%) than MCDA twin pregnancy without intervention group (86.1%), and there was no statistical difference compared with the singleton control group (39.2%). The gestational week of delivery of t MCDA twin pregnancy with intervention group (37.1±2.7) was earlier than that of the singleton control group (38.84±2.20) and later than that of MCDA twin pregnancy without intervention group (34.0±2.8). The preterm birth rate before 32 weeks and 34 weeks (5.9% and 11.8%) was lower than that of MCDA twin pregnancy without intervention group (21.8% and 46.7%), but there was no statistical difference compared with the singleton control group. The preterm birth rate before 37 weeks (30.6%) was lower than that of MCDA twin pregnancy without intervention group (78.8%) and higher than that of the singleton control group (7.6%). Conclusion There is no significant difference in the growth trend of the remaining fetus after selective feticide from those the MCDA twins without selective feticide, and its perinatal outcome is mainly related to whether there is premature rupture of membranes and premature delivery. Compared with MCDA twin pregnant women without selective feticide, the preterm birth, low birth weight, small for gestational age and NICU transfer rates of surviving newborns after selective feticide decreased to a certain extent, but they are still higher than those of normal singletons.
