Protein powder supplementation in early pregnancy and the risk of gestational diabetes mellitus: a prospective cohort study.

: Protein powder has attracted attention due to its possible adverse effects. We aimed to investigate the association of protein powder supplementation in early pregnancy with gestational diabetes mellitus (GDM) risk. : We included 6897 participants with singleton pregnancies from a prospective birth cohort. Protein powder supplementation and GDM relationships were examined by unadjusted and multivariable analysis, 1 : 2 propensity score matching, and inverse probability weighting (IPW). A multinomial logistic regression model was used to further explore the effects of protein powder supplementation on the risk of GDM subtypes. : Overall, 14.6% of pregnant women (1010) were diagnosed with GDM. In the crude and multivariable analysis before propensity score matching, participants who had received protein powder supplements were more likely to have GDM than women who did not (OR, 1.39 [95% CI: 1.07-1.79]; OR, 1.32 [95% CI: 1.01-1.72]). Protein powder supplementation was significantly associated with a higher GDM risk on IPW analysis (OR, 1.41 [95% CI, 1.08-1.83]), propensity score matching analysis (OR, 1.40 [95% CI, 1.01-1.93]) and multivariable analysis adjusted for propensity score (OR, 1.53 [95% CI, 1.10-2.12]). In the multinomial logistic regression model, protein powder supplementation was only positively associated with the risk of GDM with isolated fasting hyperglycaemia (IFH) in the crude and multivariable models (OR, 1.87 [95% CI: 1.29-2.73]; OR, 1.82 [95% CI: 1.23-2.68]). : Protein powder supplementation in early pregnancy is significantly associated with a greater risk of GDM, especially for GDM-IFH. Additional comparative studies are needed to validate these findings.