Excessive gestational weight gain in the first trimester is associated with risk of gestational diabetes mellitus: a prospective study from Southwest China

Objective: To evaluate the effects of gestational weight gain (GWG) in the first trimester (GWG-F) and the rate of gestational weight gain in the second trimester (RGWG-S) on gestational diabetes mellitus (GDM), exploring the optimal GWG ranges for the avoidance of GDM in Chinese women. Design: A population-based prospective study was conducted. Gestational weight was measured regularly in every antenatal visit and assessed by the Institute of Medicine (IOM) criteria (2009). GDM was assessed with the 75-g, 2-h oral glucose tolerance test at 24-28 weeks of gestation. Multivariable logistic regression was performed to assess the effects of GWG-F and RGWG-S on GDM, stratified by pre-pregnancy BMI. In each BMI category, the GWG values corresponding to the lowest prevalence of GDM were defined as the optimal GWG range. Setting: Southwest China. Participants: Pregnant women (n 1910) in 2017. Results: After adjusting for confounders, GWG-F above IOM recommendations increased the risk of GDM (OR; 95 % CI) among underweight (2 center dot 500; 1 center dot 106, 5 center dot 655), normal-weight (1 center dot 396; 1 center dot 023, 1 center dot 906) and overweight/obese women (3 center dot 017; 1 center dot 118, 8 center dot 138) compared with women within IOM recommendations. No significant difference was observed between RGWG-S and GDM (P > 0 center dot 05) after adjusting for GWG-F based on the previous model. The optimal GWG-F ranges for the avoidance of GDM were 0 center dot 8-1 center dot 2, 0 center dot 8-1 center dot 2 and 0 center dot 35-0 center dot 70 kg for underweight, normal-weight and overweight/obese women, respectively. Conclusions: Excessive GWG in the first trimester, rather than the second trimester, is associated with increased risk of GDM regardless of pre-pregnancy BMI. Obstetricians should provide more pre-emptive guidance in achieving adequate GWG-F.