The effectiveness of ω-3 polyunsaturated fatty acid interventions during pregnancy on obesity measures in the offspring: an up-to-date systematic review and meta-analysis

Systematic review and meta-analysis of 11 randomized controlled trials from 10 unique trials including 3644 children. Pregnant women from multiple countries and risk profiles were supplemented during pregnancy, with offspring followed for obesity-related outcomes from infancy/childhood into later follow-up.

Maternal supplementation with omega-3 long-chain polyunsaturated fatty acids during pregnancy, most often DHA alone or combined EPA plus DHA; one trial used algal DHA. Across included trials, formulations varied and four studies continued supplementation postnatally, but the review’s primary comparison was prenatal omega-3 LCPUFA versus control/placebo.

Prenatal omega-3 LCPUFA supplementation did not reduce obesity-related outcomes in offspring. Pooled estimates showed no association with BMI (SMD -0.001, 95% CI -0.08, 0.08; 2051 children), BMI-z (SMD 0.082, 95% CI -0.077, 0.24; 2511 children), body fat percentage (SMD 0.00, 95% CI -0.09, 0.09; 1641 children), fat mass (SMD 0.01, 95% CI -0.08, 0.10; 1641 children), weight, or height. Weight z score and height z score were also null, but heterogeneity was substantial (I2 90.9% and 88.4%, respectively).

Interpretation is limited by substantial heterogeneity, small sample sizes for several outcomes, and high attrition in some trials. Follow-up durations varied widely, only a subset of studies contributed to each endpoint, and differences in EPA versus DHA content, dose, timing, formulation, and postnatal continuation raise indirectness and subgroup uncertainty. Long-term effects remain unclear, and larger high-quality randomized trials are needed.