Study population
This retrospective cohort study was performed in Shanghai International Peace Maternity and Child Health Hospital (IPMCH), with approval from the research ethics committee at IPMCH as well as written informed consent provided by all participants before initiation of the study. Data were collected from the electronic medical record system of IPMCH. The study was designed based on in-hospital deliveries from Jan 2014 to Dec 2019 (Figure 1 ). A total of 78,710 births in this center were taken into consideration and analyzed. The exclusion criteria were: (1) fetal abnormalities; (2) women with renal disease; (3) women with a family history of hyperlipidemia; (4) women with diabetes mellitus. In all, a total of 78,016 eligible cases were included in the analysis.