Maternal mid-pregnancy long-chain polyunsaturated fatty acid profile is associated with pregestational body mass index and neonatal anthropometric measures at birth among non-obese pregnancies: results from two Italian multicenter cohorts

Background: Long-chain polyunsaturated fatty acids (LC-PUFAs) are essential nutrients for feto-placental development. We aimed to evaluate the associations between maternal pregestational BMI, mid-pregnancy LC-PUFA status, and delivery outcomes in non-obese pregnancies. Methods: This was a secondary analysis of two Italian cohorts including healthy non-obese women with singleton spontaneous pregnancies previously studied for maternal nutritional habits, multivitamin supplementation, blood biomarkers and infant biometry/measures. In the present analysis, included women were stratified according to pregestational BMI (normal weight (NW) versus overweight (OW) groups). Fasting venous blood samples were collected between 24 and 34 gestational weeks for fatty acid (FA) analysis. Pregnancy outcomes were recorded at delivery. Multi-adjusted generalized linear models were applied to first assess the associations between BMI-based groups and mid-pregnancy LC-PUFA concentrations, and second to evaluate the associations between the LC-PUFA profile and pregnancy outcomes. Results: 283 pregnancies were included. The OW group showed lower eicosapentaenoic acid (EPA) levels (β= -0.09; 95%CI= -0.16; -0.03) and a higher arachidonic acid/EPA ratio (β = 8.06; 95%CI = 0.00; 16.3) compared with the NW group in multi-adjusted models. After excluding women with gestational diabetes mellitus (n = 13), a significant association between LC-PUFA status and birth weight was also proved with increased birth weights in case of lower LC-PUFA n-6/n-3 ratio (β= -78.9; 95%CI= -148.5; -9.2) and higher docosahexaenoic acid (DHA) (β = 26.5; 95%CI = 0.4; 52.6), total LC-PUFA n-3 (β = 22.9; 95%CI = 0.7; 45.1) and n-3 index (β = 24.9; 95%CI = 0.03; 49.8). A positive association was further detected between LC-PUFA n-6 and neonatal ponderal index (β = 0.01; 95%CI = 0.00; 0.02). No associations were detected between LC-PUFAs and gestational age at delivery. Conclusions: These findings underscore significant associations between maternal pregestational BMI and mid-pregnancy LC-PUFA n-3 and n-6 status, with further associations with birth weight and neonatal ponderal index. Our results suggest that LC-PUFA n-3 and n-6 series may serve as valuable clinical biomarkers, particularly among OW women, and may act as predictors of intrauterine growth. Trial registration: NCT04438928.