Observational studies have suggested inconsistent results between maternal seafood consumption and the risk of adverse birth outcomes. We aimed to explore the possible dose-response relationship between seafood consumption during pregnancy and perinatal outcomes. A systematic search was performed with the use of PubMed, Web of Science, Embase and Cochrane Library from inception to October 27, 2019. Random-effects model was used to estimate pooled odds ratios (ORs) and 95% confidence intervals (CIs). Dose-response meta-analysis was carried out by using generalized least-squares regression and restricted cubic splines. Twenty-one studies with a total of 571641 participants were included in the analyses. A 45 g/day increment in seafood consumption was associated with a reduced risk of low birth weight (LBW) (OR: 0.65, 95% CI: 0.47 to 0.90) and small for gestational age (SGA) (OR: 0.84, 95% CI: 0.71 to 0.98). Additionally, there was a non-linear dose-response relationship between maternal seafood consumption and the risk of preterm birth (PTB), with no further benefit observed when intake above 45 g/day. The results for subtypes of seafood showed a modest J-shaped association between fatty fish and PTB, and the lowest risk was observed with the consumption of 30 g/day. In conclusion, higher total seafood consumption during pregnancy was associated with a lower risk of adverse birth outcomes, but the consumption of fatty fish should not exceed 30 grams per day. These findings could provide substantial evidence for dietary recommendations regarding seafood intake for pregnant women. This review was registered in PROSPERO (CRD42020152912).
Keywords: Low birth weight; meta-analysis; preterm birth; seafood; small for gestational age.