EHP - Maternal Fish Consumption And Infant Cognition

Emily Oken,¹ Robert O. Wright,^2,3 Ken P. Kleinman,¹ David Bellinger,^4,5Chitra J. Amarasiriwardena,³ Howard Hu,^3,5 Janet W. Rich-Edwards,^1,6and Matthew W. Gillman^1,7

¹Department of Ambulatory Care and Prevention, Harvard Medical School and Harvard Pilgrim Health Care, Boston, Massachusetts, USA

²Department of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, USA

³Channing Laboratory, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA

⁴Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts, USA

⁵Department of Environmental Health,

⁶Department of Epidemiology, and

⁷Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA

Address correspondence to E. Oken, Department of Ambulatory Care and Prevention, Harvard Medical School and Harvard Pilgrim, 133 Brookline Ave., Boston, MA 02215 USA. Telephone: (617) 509-9835. Fax: (617) 859-8112. E-mail: emily_oken@harvardpilgrim.org

The authors declare they have no competing financial interests.

Received February 24, 2005; Accepted May 26, 2005.

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Abstract

Fish and other seafood may contain organic mercury but also beneficial nutrients such as n-3 polyunsaturated fatty acids. We endeavored to study whether maternal fish consumption during pregnancy harms or benefits fetal brain development. We examined associations of maternal fish intake during pregnancy and maternal hair mercury at delivery with infant cognition among 135 mother–infant pairs in Project Viva, a prospective U.S. pregnancy and child cohort study. We assessed infant cognition by the percent novelty preference on visual recognition memory (VRM) testing at 6 months of age. Mothers consumed an average of 1.2 fish servings per week during the second trimester. Mean maternal hair mercury was 0.55 ppm, with 10% of samples > 1.2 ppm. Mean VRM score was 59.8 (range, 10.9–92.5). After adjusting for participant characteristics using linear regression, higher fish intake was associated with higher infant cognition. This association strengthened after adjustment for hair mercury level: For each additional weekly fish serving, offspring VRM score was 4.0 points higher [95% confidence interval (CI), 1.3 to 6.7]. However, an increase of 1 ppm in mercury was associated with a decrement in VRM score of 7.5 (95% CI, –13.7 to –1.2) points. VRM scores were highest among infants of women who consumed > 2 weekly fish servings but had mercury levels ≤1.2 ppm. Higher fish consumption in pregnancy was associated with better infant cognition, but higher mercury levels were associated with lower cognition. Women should continue to eat fish during pregnancy but choose varieties with lower mercury contamination.