New research has warned that most US women of childbearing age exceed the median blood level for two or more of three environmental pollutants that could harm brain development of fetuses and babies.
The findings were based on a new analysis of data collected from 3,173 women of childbearing age between 1999 and 2004, who participated in the Centres for Disease Control and Prevention National Health and Nutrition Examination Survey (NHANES).
Nearly 23 percent of such women met or exceeded the median blood levels for all these pollutants - lead, mercury, and polychlorinated biphenyls (PCBs) - tracked by Brown University researchers.
All but 17.3 percent of the women aged 16 to 49 were at or above the median blood level for one or more of these chemicals, which are passed to fetuses through the placenta and to babies through breast milk.
The three pollutants are of greatest interest because they are pervasive and persistent in the environment and can harm fetal and infant brain development, albeit in different ways, said study lead author Dr. Marcella Thompson.
Thompson said women aged 40 to 49 would be at greatest risk not only because these chemicals accumulate in the body over time, but also because these women were born in the 1950s and 1960s before most environmental protection laws were enacted.
Fish and heavy alcohol consumption also raised the risk of having higher blood levels. Women who ate fish more than once a week during the prior 30 days had 4.5 times the risk of exceeding the median in two or more of these pollutants. Women who drank heavily had a milder but still substantially elevated risk.
The study has been published in the journal Environmental Research.