Dietary intake patterns during pregnancy and excessive gestational weight gain: a systematic review and meta-analysis

Excessive gestational weight gain (EGWG) is associated with gestational complications and adverse birth outcomes. Dietary intake is closely related to EGWG; however, evidence of the association between different dietary patterns and EGWG is inconsistent. We conducted a meta-analysis to systematically evaluate this association using articles from PubMed, Embase, and Web of Science databases published up to March 1^st 2023 and included observational studies revealing an association between EGWG and dietary patterns during pregnancy. Dietary patterns were categorized into three groups: healthy, unhealthy, and mixed. Summary odds ratio (OR) and 95% confidence interval (CI) were calculated using the fixed-effects (I² < 50%) or random-effects model (I² ≥ 50%). Fourteen studies from eleven countries, including a total of 77,550 participants, met the inclusion criteria. The overall effect of healthy dietary patterns on EGWG was non-significant. After excluding one result in overweight participants, a significant negative association between healthy dietary patterns and EGWG was found in studies with a priori defined healthy dietary patterns (OR = 0.97, 95% CI: 0.94-1.00, P = 0.047), with sample size <1000 (OR = 0.68, 95% CI: 0.48-0.97, P = 0.031), and cohort studies (OR = 0.97, 95% CI: 0.95-1.00, P = 0.043). Overall analysis revealed a significant association between unhealthy dietary patterns and EGWG (OR = 1.22, 95% CI: 1.02-1.45, P = 0.031), and the results were similar in sub-groups of cohort studies (OR = 1.23, 95% CI: 1.02-1.49, P = 0.009) and those with a sample size < 1000 (OR = 1.31, 95% CI: 1.07-1.61, P = 0.03). A healthy dietary pattern instead of an unhealthy dietary pattern is recommended for pregnant women to prevent EGWG. This meta-analysis was registered in PROSPERO as CRD42023404179.