WOMEN who once lived in an environment polluted with lead may pass on the
poison to their unborn offspring long afterwards, according to a new study. Lead
stored in the women鈥檚 bones may be flushed out into the bloodstream during
pregnancy.
鈥淎 girl growing up in a lead-polluted environment might years later pass that
lead on to her offspring,鈥� says Bill Jameson of the National Institute of
Environmental Health Sciences (NIEHS) near Washington DC, which has analysed
data from the study. Exposure to lead in early life is known to affect mental
development.
During pregnancy, calcium may be removed from a woman鈥檚 bones and enter the
bloodstream. It is then passed across the placenta to help build the developing
embryo鈥檚 skeleton. The new study suggests that lead may also be transferred. 鈥淲e
knew lead accumulated in the bone but until now we didn鈥檛 know if the stored
lead of a mother-to-be re-entered the bloodstream during pregnancy,鈥� says
Jameson.
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The NIEHS commissioned Australian researchers to study women who had lived in
Eastern Europe before moving and becoming pregnant in Australia, where lead in
air pollution has a different ratio of isotopes. Up to 60 per cent of the lead
circulating in the women鈥檚 blood bore the Eastern European fingerprint, showing
that it had been released from their bones.
The NIEHS has studied pregnant monkeys to measure the extent to which lead in
the bloodstream penetrates the placenta. The results are still being written up,
but Jameson says that a 鈥渟ignificant鈥� amount of lead got through. The NIEHS
advises pregnant women to take calcium supplements, so that the
mineral鈥攁nd stored lead鈥攕tays locked in their bones.