Associations Between Preconception Weight Loss Drug Use, Gestational Weight Gain, and Development of Gestational Diabetes

Background: Weight loss drugs (WLD) including glucagon-like peptide-1 agonists (GLP-1 agonists) are increasingly used for obesity to promote weight loss and insulin sensitivity. Currently, recommendations are to halt all WLD in pregnancy given undetermined safety profiles or previously identified teratogenic properties. Rebound weight gain following cessation of certain WLD has been identified in prior studies. Though weight gain is anticipated in pregnancy, it is important to limit excessive weight gain. We hypothesize that prepregnancy usage of WLD influences gestational weight gain and risk of gestational diabetes. Methods: Epic COSMOS was used in this retrospective observational cohort study. Queries were run on pregnant women between February 20, 2022, and February 19, 2025. Gestational weight gain was compared between those on WLD preconception and those not on such drugs preconception. Development of gestational diabetes was also compared between the two groups. Results: Patients who utilized WLD prior to pregnancy weighed more at their initial prenatal encounter compared with those who did not. Moreover, pregestational WLD users had a higher end-of-pregnancy weight and a greater difference in body mass index between beginning and end of pregnancy, compared with nonusers. Moreover, significantly more WLD users developed gestational diabetes in pregnancy than nonusers. Conclusions: Preconception use of WLD was associated with higher gestational weight gain. With increasing prevalence in both obesity and WLD use among reproductive-aged women, further work is needed to understand the impact of cessation of WLD on gestational weight gain and on gestational diabetes risk.