Clinical Analysis Of The Changes Of Ultrasound Blood Flow In Monochorionic And Dichorionic Twin Pregnancies

Aim: To discuss the impact of chorionicity on perinatal outcomes in twin pregnancy,and to provide the guide information for clinical management by investigating the dynamic changes of uterine artery and umbilical artery of twin pregnancy and establishing mathematical models.Methods: 1.662 twin pregnancies from January 2010 to October 2017 in Obstetrics Department of the First Affiliated Hospital of Ji Nan University were selected.Clinical data of monochorionic diamniotic(MCDA)twin and dichorionic diamniotic(DCDA)twin were analysed retrospectively.The un-conditional logistic model was used to screen the risk factors.2.The ultrasonographic data of twin pregnancies were collected.The scatter plots and box plots were used for investigating the dynamic changes of uterine artery and fetus umbilical arteries of normal and abnormal twin pregnancies.The predictability of intrapair percentage differences of ultrasonic fetal biometric parameters in detecting twin discordance was assessed.Results: 1.Retrospective analysis showed that among 662 twin pregnancies,471(71.15%)were dichorionic diamniotic(DCDA)and 191(28.85%)were monochorionic diamniotic(MCDA).Rates of premature rupture of membranes,pregnancy induced hypertention,intrahepatic cholestasis of pregnancy and postpartum hemorrhage were not significantly different in dichorionic vs monochorionic pregnancies.Monochorionic twins has a higher incidence of perinatal morbidity and mortality.In monochorionic twins,the rate of twin discordance was more than twofold higher than dichorionic twins.2.Birth weight discordance was mutual risk factors for MCDA and DCDA twins with adverse perinatal outcomes.Gestational age was a protective factor in MCDA twins.Fetal distress,fetal malformations and caesarean section were risk factors and protective factor in DCDA twins,respectively.3.The analysis of artery blood flow showed that the relationship between blood flow index and gestational age:1)DCDA:UA PI=2.493-0.075*GA+0.001*(GA)~2,UA RI=0.957-0.01*GA,mean uterine artery PI=4.576-0.384*GA+0.013*(GA)~2-0.00014(GA)~3;2)MCDA:UA PI=2.725-0.088*GA+0.001*(GA)~2,UA RI=1.001-0.012*GA,mean uterine artery PI=3.793-0.261*GA+0.007*(GA)~2-5.53*10^(-5)*(GA)~3.4.There is no difference in the blood flow index between DCDA and MCDA twins in various trimesters.5.The mean uterine artery PI of sIUGR or TTTS twins is higher than normal group from 16~20 weeks of gestation.The blood flow resistance of fetus umbilical arteries in s IUGR twins increased obviously during the second trimester and kept a higher level until the third trimester.6.The prediction of twin discordance showed that:The efficiency of intrapair BPD and HC/AC differences of 10%in MC twins are 91.9%.The efficiency of intrapair FL and HC differences of 5%in DC twins are 88.6%.Conclusion:1.There are no significant differences in maternal outcomes by chorionicity;Monochorionicity is associated with increased fetal risks.Birth weight discordance was an independent risk factor both for dichorionic twins and monochorionic twins with adverse perinatal outcomes.2.The blood flow resistance of uterine artery and fetus umbilical arteries decreases in both monochorionic and dichorionic twin pregnancies with the increasing gestational age.There is no significant difference in blood flow index by chorionicity.3.The blood flow resistance of fetus umbilical arteries increases significantly in pregnant women with sIUGR during 16-20 weeks of gestation;The PI of uterine artery and the PI,RI of fetus umbilical arteries are not appropriate indicators to predict the incidence of sIUGR or TTTS,but reliable parameters for evaluating the fetal intrauterine growth and well-being.4.Intrapair BPD and HC/AC differences of 10%in MCDA twins during the second trimester were found to have significantly higher negative predictive value in detecting discordance.