Estimated optimal gestational weight gain for pregnant women with gestational diabetes mellitus: a prospective cohort study in China

Objectives We aimed to evaluate the inter-hospital variability of gestational weight gain (GWG) among women with gestational diabetes mellitus (GDM) in China and explore GDM-specific optimal GWG relative to the National Academy of Medicine (NAM) targets. Methods A prospective multicenter University Hospital Advanced Age Pregnant Cohort study was conducted from March 2017 to June 2021 at eight hospitals in China. The range of mean GWG across hospitals and the intraclass correlation coefficient (ICC) were used to evaluate the inter-hospital variability of GWG. For normal-weight and overweight women with GDM, potential optimal GWGs were derived by minimizing the joint risk of small and large for gestational age (SGA and LGA), and the incidences of adverse perinatal outcomes were compared between women who met the optimal GWGs and those who met the NAM targets. Results A total of 3,013 women with GDM and 9,115 women without GDM were included. The GWG variation among hospitals was larger in women with GDM (range: 10.0-14.1 kg, ICC = 7.1%) than in women without GDM (range: 13.0-14.5 kg, ICC = 0.7%). The estimated optimal GWGs for women with GDM were lower than the NAM targets, as 9.5-14.0 kg for normal-weight and 3.0-7.5 kg for overweight women. Women with GDM who met the optimal GWGs had lower incidences of LGA and macrosomia compared to those who met the NAM targets, with no significant increase in the incidences of SGA, preterm birth, etc. Conclusions The marked variation of GWG among hospitals in women with GDM indicates the need to develop optimal GWGs for them. The potential optimal GWGs for women with GDM might be lower than the NAM targets, likely benefiting the perinatal outcomes.