Maternal seafood consumption and fetal growth: a birth cohort study in urban China

BACKGROUND: Seafood is a good source of essential fatty acids which has a presumably beneficial effect on developing embryos and fetuses, although it is also a source of contaminants. In this context, pregnant women are faced with conflicting reports on the risk and benefits of seafood consumption. This study aims to assess whether the consumption of seafood during pregnancy was associated with fetal growth in an inland city in China. METHODS: This study included 10,179 women who delivered a singleton live birth in Lanzhou, China. Seafood consumption was assessed using a Food Frequency Questionnaire. Maternal data including birth outcomes and maternal complications information is extracted from the medical records. Associations between seafood consumption and fetal growth indicators were analyzed using multiple linear regression and multiple logistic regression. RESULTS: There was a positive association between total seafood consumption and birth weight (β = 0.027, 95%CI:0.030–0.111) but no association concerning birth length or head circumference. Seafood consumption was associated with decreased risk of low birth weight (OR = 0.575, 95% CI: 0.480, 0.689). The frequency of seafood consumption during pregnancy showed a trend toward a positive association with low birth weight. Significantly reduced rates of low birth weight were found in women who consumed more than 75 g of seafood/week during pregnancy as compared to women with no or very low intakes (P for trend 0.021). A significant interaction was observed between pre-pregnancy BMI and seafood consumption on birth weight among underweight women, but not among overweight women. Gestational weight gain partially mediated the association between seafood consumption and birth weight. CONCLUSIONS: Maternal seafood consumption was associated with decreased risk of low birth weight and increased birth weight. This association was mainly driven by freshwater fish and shellfish. These results further corroborate the present dietary recommendation to the Chinese Nutrition Society for pregnant women, especially those with underweight pre-pregnancy BMI and inadequate GWG. In addition, our findings provide implications for future interventions to improve seafood consumption among pregnant women to prevent low birth weight babies in the inland city in China.