A Comparative Study Of Pregnancy Outcomes Between Initial Twins And Reduced Twin Pregnancies In The Second Trimeser

Objective:The aim of this sthdy was to compare the outcomes of multifetal pregnancy reduced to twins with primary twin pregnancy to assess the influential factors to the reduction's pregnancy outcome,and to draw conclusions that may improve the reduced twins'management.Methods:A retrospective cohort study of twin pregnancies including 478 primary twin pregnancy,89 multifetal pregnancy reduced to twins. We analyse the average maternal ages,the gestational ages at fetal reduction and delivery, initial number of fetuses, pregnancy complications, birth weights(>28W)and the neonate outcomes.Conclusion:1. Generral Conditions The average maternal ages were29.9±5.0and 29.7±4.5 years (P=0.755) for the reduced and nonredueed groups, respectively.2. Pregnancy Outcome The mean gestational ages at delivery in the reduced and nonreduced twins were34.4±6.3 and 35.32±3.9weeks, respectively (P=0.011).The rate of extreme premature delivery (<28 weeks) was6.28%(30/478) in the nonreduced group and 14.86%(11/74)in the reduced group (P=0.002).The rate of premature delivery (<36 weeks) was 35.15%(168/4788) in the nonreduced group and 35.96% (32/89) in the reduced group (P=0.823)3. Pregnancy Complications The rate of pre-eclamepsia is 8.2%(39/478) in the nonreduced group and 12.4%(11/89) in the reduced group(P=0.199).The rate of gestational diabetes mellitus in the two groups is 1.7%(8/478) and 3.4%(3/89) to part (P=0.287).4.Birth Weight Discordance Birth weight discordance is expressed as the weight determined by A minus B, where A is the birth weight of the heavier twin and B is the birth weight of the lighter twin. The frequencies of birth weight discordances >400 g were 28.87%(138/478) for the nonreduced group and 26.97%(24/89) for the nonreduced group. The frequencies of birth weight discordances>100 g were 75.10% (359/478) for the nonreduced group and 75.28%(67/89) for the reduced group.No matter which criteria we used, the frequencies of discordant birth weights did not differ significantly between the reduced and nonreduced twin groups.5.Mean Birth Weight The gestational ages at delivery were categorized into three group:(1) 28-32W,(2) 32～36W, (3)>36W. In general, the mean birth weight of the reduced twin group was significantly lower than that of the nonreduced group.The mean birth weight of group28-32W and 32-36W are not statistically significant (P=0.545,P=0.245) The mean birth weight of group>36W are statistically significant (P<0.001)6. Neonatus Outcome The rate at least one neonate(>28W) died in the reduced and nonreduced groups were 1.23%(1/78)and2.23%(10/448).All neonatal deaths occurred were due to respiratory embarrassment,geneogenous angiocardiopathy and gastrointestinal tract malformation.The perinantal mobidity rate was 3.85%(3/78) and4.02%(18/448).There were not statistically significant in the perinantal mortality and morbidity rate (P=0.588, P=0.943),which were not effected with the initial number of fetuses.Conclusion:Multiple pregnancies after fetal reduction was still associated with a mild increased risk when compared to nonreduced twin pregnancies,the abortion rate is higer. The gestational ages of the reduced group were affected by the initial number of fetuses,and the birth weights were lower than the nonreduced twins.So we should enhance the detection and management of the mid trimester of the reduced twins.