Elsevier

Obstetrics & Gynecology

Volume 102, Issue 2, August 2003, Pages 346-351
Obstetrics & Gynecology

Decline in fish consumption among pregnant women after a national mercury advisory

https://doi.org/10.1016/S0029-7844(03)00484-8Get rights and content

Abstract

Objective

A well-publicized January 2001 federal advisory recommended that pregnant women limit consumption of certain fish because of concerns about mercury contamination. We endeavored to estimate the extent to which pregnant women changed fish consumption habits after dissemination of this national advisory.

Methods

We performed interrupted time series analysis of data from a cohort of pregnant women (2235 who completed at least one dietary questionnaire) visiting obstetric offices in a multispecialty group practice in eastern Massachusetts, surveyed before the advisory from April 1999 through December 2000 and after the advisory from April 2001 through February 2002. Main outcome measures were consumption of total fish and of four fish types: canned tuna, dark meat fish, shellfish, and white meat fish. Subjects reported fish consumption on semiquantitative food frequency questionnaires administered at each trimester of pregnancy.

Results

We observed diminished consumption of dark meat fish, canned tuna, and white meat fish after the national mercury advisory. These decreases resulted in a reduction in total fish consumption of approximately 1.4 servings per month (95% confidence interval 0.7, 2.0) from December 2000 to April 2001, with ongoing declines through the end of the study period. There was no change in shellfish intake.

Conclusion

After dissemination of federal recommendations, pregnant women in this cohort reported reduced consumption of fish, including tuna, dark meat fish, and white meat fish. Because these fish may confer nutritional benefits to mother and infant, public health implications of these changes remain unclear.

Section snippets

Materials and methods

We used an interrupted time series design16, 17 to estimate the impact of the advisory on total fish intake as well as consumption of dark meat fish, canned tuna, shellfish, and white meat fish individually. We divided the study time into three periods. The preadvisory period ran from April 1999 through December 2000. The advisory was published in January 2001. We allowed a 3-month “wash-in” period, January–March 2001, because dietary questionnaires asked about consumption up to 3 months before

Results

Table 1 presents characteristics of the 2235 participants who completed dietary questionnaires before and after the fish consumption advisory. There were 1300 subjects who completed all three dietary surveys, 365 who completed two, and 570 who completed one only. Subjects returned a total of 5200 semiquantitative food frequency questionnaires—approximately 88% completion for the first-trimester questionnaire, 72% for the second, and 90% for the third—of which 555 were completed during the

Discussion

The January 2001 federal advisory recommended that pregnant women avoid consuming predatory fish likely to contain high levels of mercury, including dark meat fish such as mackerel and swordfish.5 It also advised limiting consumption of shellfish, canned tuna, and smaller ocean fish to two to three servings per week.5

Pregnant women in this cohort consumed diminishing amounts of total fish after media attention to the adverse health effects of mercury exposure. Intake of canned tuna, dark meat

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  • Cited by (0)

    Supported by research grants from the National Institutes of Health (HD 34568, HL 64925, HL 68041) and by Harvard Medical School and the Harvard Pilgrim Health Care Foundation.

    The authors thank Stephen Soumerai, ScD, who provided guidance in performing time series analysis, experience regarding investigations of behavior change following health advisories, and helpful comments on the manuscript.

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