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.