To evaluate the associations between trimester-specific gestational weight gain (GWG) patterns stratified by pre-pregnancy body mass index (BMI) and adverse pregnancy outcomes (APOs) among Chinese women with gestational diabetes mellitus (GDM).
Approach:
Study Design: Retrospective cohort study of 8,562 singleton GDM pregnancies delivered at Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region from February 2021 to September 2025.
GWG Classification: Women were classified into underweight, normal-weight, overweight, and obesity groups by pre-pregnancy BMI. GWG was categorized as inadequate, adequate, or excessive based on National Health Commission guidelines.
Statistical Analysis: Multivariable logistic regression with Benjamini–Hochberg false discovery rate correction and generalized additive models (GAM) were used to assess associations and nonlinear relationships with APOs.
Key Findings:
Excessive GWG before OGTT diagnosis was associated with increased risk of large for gestational age (LGA) in normal-weight (aOR 1.71, 95% CI 1.38–2.13) and overweight women (aOR 1.72, 95% CI 1.26–2.37).
Excessive GWG after OGTT diagnosis was linked to increased risk of preeclampsia in normal-weight (aOR 4.06, 95% CI 2.69–6.12) and overweight women (aOR 2.49, 95% CI 1.46–4.24).
Excessive GWG before OGTT was associated with a lower risk of small for gestational age (SGA) in underweight women (aOR 0.39, 95% CI 0.25–0.62).
No significant associations were observed between GWG and APOs in women with obesity, although trends were consistent with those in the overweight group.
GAM analyses indicated nonlinear associations between GWG and several APOs.
Interpretation:
Stage-specific GWG patterns in GDM pregnancies showed heterogeneous associations with APOs across pre-pregnancy BMI categories.
Limitations:
The study is limited to a specific population in Guangxi Zhuang Autonomous Region, which may affect the generalizability of the findings.
Retrospective design may introduce biases related to data collection and accuracy.
Conclusion:
Weight management strategies tailored to pre-pregnancy BMI and gestational stage may be beneficial for women with GDM.
