Early Versus Late Multifetal Pregnancy Reduction In Triplet Pregnancies After In Vitro Fertilization/intracytoplasmic Sperm Injection

Background:Given that ongoing high-order multiple pregnancies(HOMPs)are at higher risk of maternal and neonatal complications,multifetal pregnancy reduction(MPR)has emerged as an important option to improve the obstetric outcomes in HOMPs.At present,the most widely used methods are early transvaginal MPR and late transabdominal MPR.The spontaneous loss of a fetus in utero during pregnancy is known as spontaneous reduction(SR),which occurs commonly in multiple pregnancies and can also affect pregnancy outcome by reducing the number of fetuses.To date,information regarding the optimal timing of MPR for triplet pregnancies conceived by in vitro fertilization(IVF)is based on limited and contradictory data.Objective:To compare the pregnancy outcomes as well as maternal and perinatal complications between early transvaginal MPR and late transabdominal MPR in IVF triplet pregnancies.Methods:This was a retrospective cohort study of women with triplet pregnancies who conceived by IVF/intracytoplasmic sperm injection(ICSI)from January 2011 to December 2020 in a university-affiliated reproductive center.This study included 611 triplet pregnancies after excluding women with heterotopic pregnancy.We observed spontaneous reduction occurred in part of the participants;therefore,the participants were divided into three groups according to the timing and nature of fetal reduction:women who underwent SR before 12 weeks of gestation(early SR group),those who underwent early transvaginal MPR at 6+5-8+6 gestational weeks(early MPR group),and those who underwent late abdominal MPR at 11-20 weeks(late MPR group).After adjusting for the confounding factors by multivariate logistic regression analysis,the pregnancy outcomes as well as maternal and perinatal complications were compared among the three groups.Results:1.There was SR of at least one fetus in 38.3%of triplet pregnancies.The study population was finally divided into 3 groups:SR before 12 weeks of gestation(early SR group,n=209);transvaginal MPR at 6+5 to 8+6 weeks of gestation(early MPR group,n=131);and transabdominal MPR at 11 to 20 weeks of gestation(late MPR group,n=107).60 cases in the late MPR group underwent the MPR procedure at 11-14 weeks of gestation,which was defined as the late MPR(11-14 weeks)group.2.After adjusting for the confounding factors,the early MPR group had a higher risk of postprocedural fetal loss than the late MPR group[13.7%vs.3.7%,P=0.007,odds ratio(OR):4.84,95%confidence interval(CI):1.54 to 15.20],and the risk of one-fetus loss after early MPR was significantly higher than in the late MPR group(14.5%vs.5.6%,P=0.020,OR:3.23,95%CI:1.20-8.65).Singletons born after early MPR had a higher mean birth weight than those in the late MPR group(3268±516g vs.2955±626g,P=0.010).There was no significant difference in the incidence of pregnancy loss,preterm birth,gestational diabetes mellitus(GDM),hypertensive disorders of pregnancy(HDP),preterm premature rupture of membranes,(PPROM),low birth weight(LBW),very low birth weight(VLBW),small for gestational age(SGA),or neonatal morbidity between early MPR and late MPR either in singleton or twin pregnancies.3.Singletons born after early SR had a higher mean birth weight than those after late MPR at 11-14 weeks(3225±568g vs.2964±543g,P=0.027).After adjusting for the confounding factors,no significant difference was manifested in the pregnancy outcomes as well as maternal and perinatal complications among the early SR and MPR groups in terms of gestational age at delivery,pregnancy loss rate,preterm delivery rate,LBW rate,and SGA rate,among others.Conclusion:Early MPR significantly increased the risk of postprocedural fetal loss compared to late MPR with comparable pregnancy outcomes as well as maternal and neonatal complications.And the overall SR rate was 38.3%,of which 89.3%occurred before 12 gestational weeks.Moreover,the outcomes after early SR before 12 weeks of gestation are not inferior to the MPR groups.Considering the high SR rate during early pregnancy and the increased risk of postprocedural fetal loss in early MPR,late MPR might be a preferable choice for fetal reduction in multiple pregnancies following IVF.