June 8, 2006
Some hypertension drugs risky in early pregnancy
By Gene Emery
BOSTON (Reuters) - A class of widely used blood pressure
drugs once considered safe in the early stages of pregnancy can
nearly triple the risk of birth defects, a study showed on
The drugs, known as ACE inhibitors, were only thought to
cause problems when taken after the third month of pregnancy.
But the study of nearly 30,000 births logged in Tennessee's
Medicaid program and published in this week's New England
Journal of Medicine shows the risk exists from the beginning.
Because women can unknowingly be pregnant for a month or
two, such drugs should be avoided by women likely to become
pregnant or trying to conceive, according to the study.
"Our data suggest that such exposures cannot be considered
safe and should be avoided," said the team led by William
Cooper of the Vanderbilt University School of Medicine.
"There's a lot of other blood pressure medicines that can
be used for a woman who might become pregnant," he told
Use of the drugs among women age 15 to 44 nearly doubled
from 1995 to 2002, in part because they are also used to ward
off 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
Nearly two in five of those babies had multiple defects,
most involving the heart and central nervous system.
In contrast, the risk was 1.7 percent for the 202 women
taking other blood pressure medicines. The rate among the
29,096 women taking no blood pressure drugs at all was 2.6
percent, according to the study.
That may not be a lot of babies, but "there's a potential
for risk that's completely preventable," Cooper said.
Women with diabetes, which can also produce defects, were
excluded from the study.
In a Journal editorial, Jan Friedman of the University of
British Columbia in Vancouver said the results need to be
confirmed. "This is not the last word on the subject, but it is
shocking to realize that it is almost the first."
Little information is known about the effects of most drugs
on the fetus.
The information is not available when a new drug is
approved by the U.S. Food and Drug Administration because
manufacturers are usually not required to actively look for
The voluntary reporting system that spots some side effects
"is a notoriously inefficient and often misleading method of
identifying such effects," said Friedman. "Nevertheless, drugs
are often prescribed for pregnant women."