Ahead by a Hair: Preterm Delivery and Maternal Mercury Intake

Abstract

Vol. 115, No. 1 EnvironewsOpen AccessAhead by a Hair: Preterm Delivery and Maternal Mercury Intake John Tibbetts John Tibbetts Search for more papers by this author Published:1 January 2007https://doi.org/10.1289/ehp.115-a43aAboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit Pregnant women often receive confusing information about whether or not they should consume fish and fish oils. Protein and unsaturated fatty acids in fish confer health benefits. Yet numerous studies have suggested that fish consumption is a major source of mercury exposure, and scientists have raised concerns that mercury levels safe for adults could pose a hazard to the developing fetus. Now a new study suggests another possible hazard associated with mercury exposure during pregnancy: preterm delivery [EHP 115:42–47; Xue et al.].The Pregnancy Outcomes and Community Health study, conducted by researchers at Michigan State University, is the first large, community-based study to examine the risk of preterm birth in relation to mercury concentrations among women with low to moderate exposure to the contaminant. This study is also the largest in the United States to correlate fish consumption and maternal hair mercury. Hair levels of total mercury reflect a longer window of contaminant exposure (for example, across the first half of pregnancy) than blood levels, which reflect recent exposure.The researchers examined maternal hair mercury levels during mid-pregnancy (between weeks 15 and 27) in 1,024 women from 52 prenatal clinics in five Michigan communities. This state borders on four of the five Great Lakes, giving the women easy access to sport-caught fish, which can be relatively high in mercury. Each community included urban, suburban, and rural areas.The women reported the amount and category of fish they consumed from the beginning of the current pregnancy through the time of the interview. Canned fish was the most frequently eaten fish category during the first six months of pregnancy, followed by fish bought at a store or restaurant. Only 9.2% of women reported consuming sport-caught fish during the first six months of pregnancy, and almost none ate shellfish. These women’s levels of reported fish consumption would be considered moderate to low when compared to populations that subsist on fish.The researchers took hair samples from close to the scalp to approximate exposure during the pregnancy to date, then assessed them for total mercury levels. They found that total fish consumption correlated positively with mercury levels in hair. Women who delivered before 35 weeks had three times the odds of having hair mercury levels at or above the 90th percentile (0.55–2.5 μg/g), compared with women delivering at term (37 weeks or later). Although the study sample was large, the small number of women delivering before 35 weeks (44) means more studies are needed to test this association.Predictor of preemies?Measures of mercury in maternal hair may predict risk for preterm delivery.FiguresReferencesRelatedDetails Vol. 115, No. 1 January 2007Metrics About Article Metrics Publication History Originally published1 January 2007Published in print1 January 2007 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]s.nih.gov. Our staff will work with you to assess and meet your accessibility needs within 3 working days.