Popular hypertension drugs triple the risk of birth defects

Jun 8 2006

A study by American researchers has found that certain widely used hypertension drugs, once considered safe in the early stages of pregnancy, can almost triple the risk of birth defects.

It was always considered that drugs, known as ACE inhibitors only caused problems when taken after the third month of pregnancy but this latest study demonstrates that this is not the case at all.

The drugs already carry a warning that they may cause injury and even death to the developing fetus when used during the second and third trimesters of pregnancy.

The research team was led by William Cooper, M.D., M.P.H., associate professor of Pediatrics at the Monroe Carell Jr. Children's Hospital at Vanderbilt University School of Medicine.

They examined records of 29,507 births logged into Tennessee's Medicaid program and found the risk from ACE inhibitors exists from the beginning of the pregnancy.

As women can unknowingly be pregnant for a month or two, the team say such drugs should be avoided by women likely to become pregnant or trying to conceive.

The researchers say their data suggests that such exposures cannot be considered safe and should be avoided and advise women in that situation to use other blood pressure medicines suitable for women who might become pregnant.

The use of such drugs among women age 15 to 44 has almost doubled between 1995 and 2002, partly because they are also used to prevent kidney damage in people with diabetes.

The researchers found that among the 209 pregnant women who took any of the 10 or so ACE inhibitor drugs in their first three months of pregnancy, 7.1 percent delivered a child with a major malformation.

Nearly two in five of those babies had multiple defects, most involving the heart and central nervous system.

According to the study the risk was 1.7 percent for the 202 women taking other blood pressure medicines and among the 29,096 women taking no blood pressure drugs at all it was 2.6 percent.

Women with diabetes, which can also produce defects, were excluded from the study.

Cooper says that though that may not seem to be a lot of babies, it is a risk that is completely preventable.

It appears that such information is not available when a new drug is approved by the U.S. Food and Drug Administration because manufacturers are not required to actively look for such problems and little is is known about the effects of most drugs on the fetus.

The Food and Drug Administration is apparently examining the study data.

The research is published in the current edition of the New England Journal of Medicine.