Washington: Most women in the childbearing age showed up excessive levels of two or three environmental pollutants such as lead, mercury and poychlorinated biphenyls (PCBs) that could harm the brain development of foetuses and babies, according to a survey.
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 - tracked by Brown University researchers, the journal Environmental Research reported.
All but 17.3 percent of the women aged 16 to 49 years were at or above the median blood level for one or more of these chemicals, which are passed to foetuses through the placenta and to babies through breast milk, according to a Brown statement.
The three pollutants are of greatest interest because they are pervasive and persistent in the environment and can harm foetal and infant brain development, albeit in different ways, said Marcella Thompson of Brown, who led the study.
Thompson said women aged 40 to 49 years 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.