Background and purpose: With the popularization of a two-child policy in China, the number of pregnant women of advanced maternal age will increase steadily. We aimed to assess the association between pre-pregnancy body mass index (BMI) and weight gain in the first and second trimester and the risk of gestational diabetes (GDM) in the advanced maternal age group and control group defined as maternal age of 20-35 years.
Results: The risk of GDM for obesity before pregnancy was 2.707 (95% CI: 1.042-7.029) folds and 3.612 (95% CI: 1.182-11.039) folds in the control group and advanced maternal age group, respectively. Excessive weight gain in the first trimester was significant related to a higher risk of developing GDM with the odds ratio (OR) of 2.655 (95% CI: 1.265-5.571) and 4.170 (95% CI: 1.437-12.100) in the control group and advanced maternal age group, respectively.
Materials and methods: This prospective cohort study included 565 pregnant women with singleton pregnancy who were recruited in their first prenatal visit from the antenatal clinic in March and December 2016. Maternal weight was recorded before pregnancy, in the first prenatal visit and at the time of screening oral glucose tolerance test (OGTT). All women underwent 2 h 75g-OGTT at 24-28 weeks (24 weeks on average). GDM was diagnosed according to the standards issued by the Ministry of Health of China in 2011.
Conclusions: Elevated pre-pregnancy BMI independently increases the risk of GDM, particularly in advanced maternal age. Excessive weight gain in the first trimester is significantly associated with the incidence of GDM regardless of pre-pregnancy BMI.
Keywords: advanced maternal age; excessive gestational weight gain; gestational diabetes; pre-pregnancy body mass index.