Gestational weight gain and the risk of gestational diabetes mellitus: A latent class trajectory analysis using birth cohort data

To explore trajectories of gestational weight gain (GWG) before diagnosis and its association with risk of gestational diabetes mellitus (GDM).A population-based retrospective cohort study including 37,060 women with live singleton was conducted between 2013 and 2019 in China. Latent class trajectory model (LCTM) was used to identify GWG trajectories, and Poisson regression with robust error estimates was used to estimate risk ratio (RR) of GDM.Among total 37,060 participants, 25.47% of women were developed with GDM. Two trajectories of GWG were identified as non-excessive weight gain (94.31%) and excessive weight gain (5.69%) before diagnosis of GDM. Women with excessive GWG trajectory before diagnosis had significantly 32.8% (aRR = 1.328, 95 %CI: 1.252 ∼ 1.409, P < 0.001) increased risk of developing GDM compared with non-excessive GWG trajectory. Women with excessive GWG trajectory also had higher risk of macrosomia (aRR = 1.476, 95 %CI: 1.307 ∼ 1.666, P < 0.001) and cesarean delivery (aRR = 1.126, 95 %CI: 1.081 ∼ 1.174, P < 0.001). The impact of excessive GWG trajectory on GDM was greater among pre-pregnancy normal weight women compared with overweight/obese or underweight women.Women with excessive GWG trajectory before diagnosis had significantly higher risk of GDM and GDM-related adverse outcomes, and pre-pregnancy normal weight women with excessive GWG trajectory should also be concerned.