Fish consumption prior to pregnancy and pregnancy outcomes in the National Birth Defects Prevention Study, 1997-2011.

Objective: To evaluate the relationships between maternal fish consumption and pregnancy outcomes in a large, population-based sample of women in the USA.

Design: We collected average fish consumption prior to pregnancy using a modified version of the semi-quantitative Willett FFQ. We estimated adjusted OR (aOR) and 95 % CI for associations between different levels of fish consumption and preterm birth (<37 weeks), early preterm birth (<32 and <35 weeks) and small-for-gestational-age infants (SGA; <10th percentile).

Setting: The National Birth Defects Prevention Study (NBDPS).

Subjects: Control mother-infant pairs with estimated delivery dates between 1997 and 2011 (n 10 919).

Results: No significant associations were observed between fish consumption and preterm birth or early preterm birth (aOR = 0·7-1·0 and 0·7-0·9, respectively). The odds of having an SGA infant were elevated (aOR = 2·1; 95 % CI 1·2, 3·4) among women with daily fish consumption compared with women consuming fish less than once per month. No associations were observed between other levels of fish consumption and SGA (aOR = 0·8-1·0).

Conclusions: High intake of fish was associated with twofold higher odds of having an SGA infant, while moderate fish consumption prior to pregnancy was not associated with preterm or SGA. Our study, like many other studies in this area, lacked information regarding preparation methods and the specific types of fish consumed. Future studies should incorporate information on nutrient and contaminant contents, preparation methods and biomarkers to assess these relationships.