First-trimester Fatty Liver Index and Subsequent Incidence of Gestational Diabetes Mellitus: A Community-based Prospective Cohort Study in South India

Background: Early-pregnancy metabolic risk markers are useful in the identification of women at increased risk of developing gestational diabetes mellitus (GDM), and hepatic steatosis is one of the established predictors of GDM. This study aims to assess the role of Fatty Liver Index (FLI), a noninvasive screening tool for hepatic steatosis, during the first trimester of pregnancy and its association with the incidence of GDM. Methods: This prospective cohort enrolled 368 first-trimester pregnant women from seven primary health centres in Puducherry, South India, after excluding women with pre-existing or baseline-detected diabetes mellitus. FLI was calculated from body mass index, waist circumference, triglycerides, and gamma-glutamyl transferase. GDM was defined by DIPSI criteria as a 2-hour glucose value ≥140 mg/dL after a 75-g oral glucose load, irrespective of fasting status. Adjusted relative risks (aRRs) were estimated by binomial regression. Results: Fourteen pregnancies ended in abortion before outcome assessment, and 354 women completed testing. GDM developed in 90/354 (25.4%): 36/88 (40.9%) among women with elevated FLI (FLI >32) and 54/266 (20.3%) among those with normal FLI. Elevated FLI remained significantly associated with GDM after adjustment (aRR 1.80, 95% CI 1.29–2.52). Each 10-point increase in FLI was associated with higher adjusted risk (aRR 1.11; 95% CI 1.04–1.17). Conclusions: Elevated first-trimester FLI was associated with subsequent GDM incidence. Incorporating FLI as a noninvasive screening tool in primary care can enable early metabolic risk stratification and guide timely interventions to prevent GDM and associated adverse maternal and neonatal outcomes, but its modest discriminative power does not support replacing universal GDM testing.