Early pregnancy body mass index outweighs gestational weight gain in predicting gestational diabetes mellitus: A single-center experience from Türkiye.

Abstract

Introduction: Gestational diabetes mellitus (GDM) is a common pregnancy complication associated with maternal and neonatal morbidity. Various risk factors for GDM, including pre-pregnancy body mass index (BMI) and gestational weight gain (GWG), have been described in the literature. Although both factors have been identified as important risk factors for GDM, the relative contribution of each to the development of GDM remains controversial. In this retrospective observational study, we aimed to compare the relative impact of early pregnancy BMI and GWG on the risk of developing GDM in a study from a single tertiary center.

Materials and methods: Our retrospective study analyzed data from pregnant women who were referred to our clinic between 2017 and 2024 and underwent a 75-g oral glucose tolerance test (OGTT) between the 24^th and 28^th weeks of gestation. Sociodemographic characteristics, plasma glucose levels at 0, 1, and 2 hours during the OGTT, maternal height and self-reported weight at the onset of pregnancy (when informed of the positive pregnancy test), and body weight at the time of the OGTT were retrieved.

Results: Among the 290 pregnant women included in the study, 45 (15.5%) were diagnosed with GDM. In the multivariate logistic regression analysis, advanced maternal age (p = 0.034), a prior history of GDM (p = 0.043), excessive gestational weight gain (adjusted odds ratio [aOR] = 2.989; p = 0.042), and elevated early pregnancy BMI (aOR = 4.317; p = 0.025) were identified as independent risk factors for GDM.

Conclusion: The findings of our study showed that pre-pregnancy BMI was independently associated with a higher risk for GDM compared to gestational weight gain. Additionally, advanced age and a history of GDM were independent risk factors for GDM. These results suggest that clinicians should focus on pre-pregnancy BMI assessment and gestational weight monitoring to reduce the risk of GDM.