Development of Fetal Growth Charts in Twins Stratiﬁed by Chorionicity
and Mode of Conception: a Retrospective Cohort Study in China
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.