Study design
We performed a retrospective case–control study, using data on all
prenatal visit and discharges from Shanghai First Maternity and Infant
Hospital for the period of January 1st, 2017 to July
31th, 2021 to evaluate the effect of maternal weight
gain in different periods of pregnancy on VTE at any site. Written
informed consent was obtained from the participants. The data including
maternal demographical characteristics, reproductive history, as well as
clinical information related to this pregnancy were collected. This
study was approved by Ethics Committee of Shanghai First Maternity and
Infant Hospital (reference number: KS2057).