Yuanqing Xia

and 6 more

Objectives: We attempted to establish a set of fetal biometric references for Chinese twin pregnancies, stratified by chorionicity and conception mode as spontaneously conceived monochorionic diamniotic (SC-MCDA), spontaneously conceived dichorionic diamniotic (SC-DCDA) and assisted reproductive technology dichorionic diamniotic (ART-DCDA). Design: Retrospective cohort study. Setting: International Peace Maternity & Child Health Hospital, shanghai, China. Population or Sample: 929 twin pregnant women, along with 2019 singleton pregnant women, were qualified for the inclusion criteria. Methods: The linear mixed models were used to test the difference of growth pattern between groups, and the growth curve of each biometric parameter was modeled by generalized additive model for location scale and shape. Main Outcome Measures: From 2016 to 2019, ultrasonographic fetal biometric measurements were longitudinally collected in pregnant women, in which six measurements were recorded: fetal weight, biparietal diameter, head circumference, abdominal circumference, femur length and humerus length. Results: Overally, SC-DCDA twins grew faster than SC-MCDA twins, while slower than ART-DCDA twins. Correspondingly, the week-specific differences between groups were also identified for all the six biometric measurements, though the differences were not observed in all gestational weeks. The customized fetal growth charts of each fetal biometric parameter were then respectively constructed for SC-MCDA, SC-DCDA and ART-DCDA twins, and all of the three shows significant difference from singletons, especially during the third trimester. Conclusions: The fetal biometric trajectories demonstrated characterized pattern according to chorionicity and conception mode. We are the first to curve fetal biometric reference values for Chinese SC-MCDA, SC-DCDA and ART-DCDA twin pregnancies.