Data collection and measures
Data for each delivery in the center were recorded on the electronic medical system. Maternal baseline characteristics including medical and reproductive histories were collected at the first antenatal visit during 9 to 14 weeks of gestation. Pre-pregnancy weight data were collected from records of pre-pregnancy physical examinations within 1 year and BMI was calculated at the first antenatal care visit. Women with a BMI ≥ 25 kg/m2 were defined as obese.
Maternal blood pressure was measured based on a previous study.(14) Clinical serological examinations were required at the first prenatal care visit before 14 weeks of gestation. Blood samples from all participants were collected in fasting conditions between 7:00 am and 9:00 am. Serum was separated and stored at -40℃ until analyzed further. TG concentrations were performed by enzymatic assay (Roche Diagnostics, Mannheim, Germany) and a Cobas c702 analyzer. The inter-assay coefficient of variations was < 2.5% for TGs. The cut-off point of maternal TG at the 90th (2.04 mM) percentile was defined according to our previous study.