Although most women experience a rise in blood pressure late in pregnancy, levels that are too high are linked to the dangerous pregnancy complication, preeclampsia.

Preeclampsia can strike without warning, causing blood pressure to rise to dangerously high levels. The condition may progress to eclampsia, in which high blood pressure and convulsions could be fatal to the mother or child. Preeclampsia is a leading cause of maternal death. It strikes about 5% of first-time mothers and 1% to 2% of mothers during subsequent pregnancies.

Previous research in both men and women has shown that blood lead levels can contribute to an increase in blood pressure.

According to the report in the December issue of the American Journal of Epidemiology, Dr. Stephen J. Rothenberg and colleagues tested lead levels in the heel and shinbones of more than 1,000 women in the final trimester of pregnancy. They found that for each incremental increase in lead in the heel bone, the risk for elevated blood pressure went up.

Levels of lead in bone are a measure of past exposure to the toxic substance. However, they note that the lead did not seem to pose a major risk to the pregnant women.

"The increased risk of hypertension associated with increased bone lead in pregnant women is small," write Rothenberg and colleagues.

"However, given the prevalence of hypertension during pregnancy, the past lead exposure of a population will significantly increase the underlying rate of hypertension," they conclude.

The authors note that even women with low levels of lead in the blood--a sign of current exposure--may still be at risk for high blood pressure due to past lead exposure. During pregnancy, bone is broken down to contribute calcium to the developing fetus; a situation that can release stored lead into the blood.

"Controlling blood pressure may require reduction of lead exposure long before pregnancy," they conclude.

"Clearly this work gives additional urgency to worldwide efforts to reduce and prevent lead exposure in the workplace and community," according to a commentary by Howard Hu and Mauricio Hernandez-Avila, of the Department of Environmental Health at Harvard School of Public Health in Boston, Massachusetts. In addition, it gives added incentive to find ways--such as nutritional supplements--to try to reduce lead in the body after exposure.

SOURCE: American Journal of Epidemiology 2002; 156:1079-1087.

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Start using Essential Daily Defense BEFORE you get pregnant to help prevent and remove the lead burden (now estimated at 1000 times more prevalent in us than in pre-industrial times) in your bones from going into your children's bones and brain.