325-OR: Gestational Diabetes Mellitus (GDM) Is Associated with Higher Fat Mass (FM) Accretion in Male Infants during Early Postnatal Period

Introduction and Objective: Infants of women with GDM can exhibit higher FM accretion in the early postnatal period, but sex-specific trajectories of FM and fat-free mass (FFM) remains unknown Methods: In a UK multi-ethnic cohort of 925 mother-infant pairs (18.5% GDM), body composition was assessed using air displacement plethysmography (PEAPOD) at birth, 4 weeks, and 5 months. Complete dataset with PEAPOD measurements were available for 325 infants (18.5% GDM). Linear mixed-effects models were used to analyse the percent FM, FFM, FM index (FMI) and FFM index (FFMI) trajectories normalised for length Results: At birth, infants born to GDM mothers had similar FM, but lower FFM compared to non-GDM (mean±SD: FM=0.33±0.17 vs 0.36±0.17; p=0.11 and FFM=2.82±0.30 vs 2.97±0.39; p=0.001). Infants exposed to GDM gained 177g more FM with a 21.1% faster growth rate compared to non-GDM. This was mainly observed in male infants born to GDM mothers (FMI mean difference:1.25 kg/m2; 95% CI: 0.68, 1.81) from birth to 5 months compared to non-GDM, after adjusting for maternal and infant covariates, including breastfeeding. However, no significant differences in FFM or FFMI growth rates were observed between male infants exposed to GDM and non-GDM (FFMI mean difference: 0.05 kg/m²; 95% CI: -0.77 to 0.87) Conclusion: Male infants exposed to GDM gained faster and higher FM accretion compared non-GDM. Despite lower FFM at birth in GDM, there was no catch up of FFM Disclosure N. Periyathambi: None. C. Bagias: None. Y. Ghebremichael-Weldeselassie: None. N. Sukumar: None. P. Saravanan: None. Funding Partly supported by: Medical Research Council, UK (MR/N006232/1)