Association of atherogenic index of plasma with gestational diabetes mellitus and birth weight outcomes, and the mediating role of blood glucose.

AIMS: This study aimed to examine the associations of maternal first-trimester atherogenic index of plasma (AIP) with gestational diabetes mellitus (GDM) and birth weight outcomes, and the mediating role of second-trimester blood glucose. METHODS: This prospective cohort study included 5,706 pregnant women without pre-existing diabetes or other chronic diseases. AIP was calculated as log10[TG (mg/dL)/HDL-C (mg/dL)] from fasting lipid profiles. Generalized linear models and mediation analysis were used to assess the relationships between AIP and outcomes, and the mediating effects of blood glucose. RESULTS: Participants had a mean maternal age of 29.3 years, a mean first-trimester AIP of 0.28 ± 0.19, GDM prevalence of 20.64%, and mean neonatal birth weight of 3314.05 ± 442.11 g. A 1-unit increase in first-trimester AIP was associated with greater birth weight (β: 93.12 g, 95% CI: 39.38-146.87), elevated GDM risk (RR: 2.08, 95% CI: 1.52-2.85), and higher risk of large-for-gestational-age infants (RR: 1.67, 95% CI: 1.09-2.58). A nonlinear association was identified between first-trimester AIP and birth weight, with a 158.95 g (β: 158.95 g, 95% CI: 90.70-227.20) rise per 1-unit elevation in AIP above 0.14. Fasting plasma glucose (FPG) mediated 28.35% of the association between AIP and birth weight, rising to 60.04% among women with GDM. The third-trimester rise in AIP was significantly smaller in women with GDM. CONCLUSIONS: First-trimester AIP appears to correlate with GDM and birth weight. Second-trimester FPG mediates this association, particularly in mothers with GDM. These findings support the clinical value of early lipid monitoring in prenatal care.