Moderate Fish Intake May Lower Risk for Repeat Preterm Birth

Laurie Barclay, MD

April 26, 2011

April 26, 2011 — Moderate fish intake is associated with a lower risk for subsequent preterm birth, according to the results of a study reported in the May issue of Obstetrics & Gynecology. This study was ancillary to a randomized trial of omega-3 supplementation in women at high risk for preterm birth.

"Eating fish has been associated with reductions in preterm birth, increased duration of pregnancy, or both reductions in preterm birth and increased duration of pregnancy in some but not all studies; most studies have been conducted in unselected or low-risk women," write Mark A. Klebanoff, MD, MPH, from Nationwide Children's Hospital in Columbus, Ohio, and colleagues from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units Network. "Several reports have found the association between fish consumption and pregnancy outcome to be nonlinear."

The goal of the study was to estimate the association between fish intake and erythrocyte omega-3 long-chain polyunsaturated fatty acids with preterm birth in a cohort of women at high risk because of at least 1 previous spontaneous preterm delivery. Participants completed a questionnaire regarding dietary fish consumption. Erythrocyte fatty acids were measured at enrollment at 16 to 21 completed weeks of gestation. Linear and quadratic terms were used to model the association between fish intake and preterm delivery.

Among women eating fish less than once per month, the probability of preterm birth was 48.6% vs 35.9% among women who reported more frequent fish consumption (P < .001). For moderately frequent fish intake, defined as 3 servings per week, the adjusted odds ratio (OR) for preterm birth was 0.60 (95% confidence interval, 0.38 - 0.95). Women who ate more than 3 servings of fish per week had no further reduction in the risk for preterm birth.

There was a weak, but significant, correlation of erythrocyte omega-3 levels with frequency of fish intake (Spearman r = 0.22; P < .001). Compared with women in the highest 3 quartiles of erythrocyte omega-3 levels, those in the lowest quartile were more likely to report consuming less than 1 fish meal per month (40.3% vs 26.3%, respectively; P < .001).

"Moderate fish intake (up to three meals per week) before 22 weeks of gestation was associated with a reduction in repeat preterm birth," the study authors write. "More than moderate consumption did not confer additional benefit. These results support the recommendations of the U.S. Food and Drug Administration [FDA] and the American Congress of Obstetricians and Gynecologists [ACOG] for fish consumption during pregnancy."

Limitations of this study include few measures of socioeconomic factors that might be associated with fish consumption, lack of data on diet other than frequency of fish intake up to the time of randomization, and lack of assessment of biomarkers of environmental contaminants or nutrients other than omega-3 and omega-6 fatty acids. Other limitations include possible error in report of fish consumption and lack of generalizability to other populations of pregnant women.

"However, from a clinical perspective our data suggest that docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA] supplementation cannot take the place of fish consumption with respect to any benefits there might be for preterm birth," the study authors conclude.

The NICHD supported this study. Views expressed in the journal article do not necessarily represent the official views of the NICHD or the National Institutes of Health. The study authors have disclosed no relevant financial relationships.

Obstet Gynecol. 2011;117:1071-1077. Abstract


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