The Influence Of Timing And Method Of Fetal Reduction On Perinatal Outcomes Of Dichorionic Diamniotict Twin And Trichorionic Triamniotic Triplet Pregnancies

Over the past three decades,due to the widespread application of ovulation induction agents and the promotion of assisted reproductive technologies,the incidence of multifetal pregnancy has increased significantly.Multifetal pregnancies not only increase maternal risk,but also increase fetal morbidity and mortality.Multifetal pregnancy reduction(MFPR)is designed to effectively reduce the complications of multifetal pregnancy,and it can be carried out throughout the whole gestation.According to the time and method of reduction,MFPR can be divided into early transvaginal pregnancy reduction and mid-term transabdomial pregnancy reduction.Early transvaginal pregnancy reduction is widely carried out domestic and overseas because of its safety and easy operation.However,in the case of multifetal pregnancy missed in the early pregnancy and one abnormal fetus found in the second trimester of pregnancy,only mid-term transabdominal pregnancy reduction can be selected clinically.Mid-term transabdominal reduction can be performed after nuchal translucency test,chorionic villus detection and other detailed fetal screening.Dichorionic diamniotict twin pregnancies and trichorionic triamniotic triplet pregnancies are the two most common types of multifetal pregnancy clinically.Previous studies have confirmed both early pregnancy reduction and mid-term pregnancy reduction can improve the pregnancy outcomes of multifetal pregnancies.However,there were few studies comparing the pregnancy outcomes of the two groups after different surgical procedures.ObjectiveThe purpose of this study was to compare the perinatal outcomes of two clinically common multifetal pregnancy types after early transvaginal pregnancy reduction or mid-term transabdominal pregnancy reduction,and to explore the safety and effectiveness of mid-term transabdominal pregnancy reduction,providing data support for future clinical work.MethodThe study group included a cohort of 305 patients underwent MFPR at the Reproductive Medical Center of the First Affiliated Hospital of Zhengzhou University from January 2008 to December 2015.Data on all the patients were retrieved from the medical records,including maternal age,gravidity,parity,mode of conception,primary numbers of fetus,chorionicity,indications of fetal reduction,fetal reduction procedures,remaining numbers of fetus and other clinical data.Main measurements included abortion rate,mean gestational age at delivery,preterm birth rate less than 34 weeks,preterm birth rate less than 37 weeks,average birth weight,incidence of hypertensive disorder complicating pregnancy(including gestational hypertension and preeclampsia),gestational diabetes,small for gestation age,preterm premature rupture of membranes,etc.Statistical analysis of these data was performed using the SPSS 17.0 computer package between groups.Results 1 From trichorionic triamniotic triplet pregnancies to dichorionic diamniotict twin pregnancies group.There was no difference in maternal age,maternal gravidity and parity status among the early transvaginal pregnancy reduction group(n=144)and the mid-term transabdomial pregnancy reduction group(n=24).The difference in mode of conception between the two groups was statistically significant.The abortion rate in the early group was higher than that in the late group(16.7% vs.8.3%),but the difference was not statistically significant.The mean gestational age in the early group(36.598±2.191 w vs.36.012±1.561w)and the mean birth weight(2548.14±480.777 g vs.2365.24±415.817g)were better than those in the mid-term group,but after adjusting for confounding factors(pregnancy patterns),there was no the statistical significance.In the early group,the incidence of preterm birth rate less than 37 weeks(45.8% vs.72.7%)and small for gestation age(30.0% vs.54.5%)were lower than those in mid-term group.After adjusting the confounding factors,the difference was still statistically significant.The rate of pregnancy complications such as hypertensive disorders,gestational diabetes,and preterm premature rupture of membranes were comparable between the two groups.2 From dichorionic diamniotict twin pregnancies to singleton group.Between the early transvaginal pregnancy reduction group(n=87)and the mid-term transabdomial pregnancy reduction group(n=50),no clinical or statistical significance was found regarding background characteristics except for the mode of conception.The abortion rate in the early and mid-term groups was similar(14.9% vs.14.0%).There were no neonatal deaths in 74 patients in the early group and in 43 patients in the mid-term group.In the early group,the preterm birth rate less than 34 weeks(6.8% vs.7.0%)was lower than that in the mid-term group,and the difference was not significant.Although in the early group,the preterm birth rate was less than 37 weeks(16.2% vs.14.0%),the average gestational age of delivery(38.174±2.263 vs.38.013±2.407),and the average birth weight of newborns(3099.59±652.299 vs.3099.59±652.299)were greater than those of the mid-term group.However,the differences were not statistically significant.In addition,the rate of pregnancy complications such as hypertensive disorders,gestational diabetes,small for gestation age and preterm premature rupture of membranes were similar between the two groups.ConclusionsFor dichorionic-diamniotict twin pregnancies,based on the safety and effectiveness of the mid-term transabdomial pregnancy reduction,mid-term transabdominal reduction can be performed after nuchal translucency test,chorionic villus detection and other detailed fetal screening.Due to the high incidence of preterm birth rate less than 37 weeks and small for gestation age,early transvaginal pregnancy reduction is a better choice for trichorionic-triamniotic triplet pregnancies.