A new study suggests a link between the amount and type of fish consumed by a pregnant woman and mercury exposure may affect fetal growth. The study was designed as a prospective, population-based mother-infant cohort study and is reported in the August 26 Online First issue of the American Journal of Clinical Nutrition.

The objective of the study was to assess the association of consumption of different types of fish and prenatal mercury exposure with birth weight, birth length, and classification as small for gestational age (SGA) in newborns.

When the mothers inthe top 25% of mercury exposure were compared to those in the lowest 25% of exposure, the study noted a 143.7 gm difference in birth weigh which was statistically significant (95% confidence interval [CI], –251.8 to –35.6; P for trend = .02)

The study also noted that mothers who consumed less than 1 portion of canned tuna per month had a lower risk of delivering an SGA newborn than those consuming 2 or more portions per week had newborns.

The study authors conclude that “the role of fish in fetal growth depends on the amount and type of fish consumed,” They also suggest that the findings regarding mercury exposure warrant further study

Abstract