ACE inhibitors, a popular class of drugs for hypertension, may cause birth defects if taken during the first trimester of pregnancy, an American study has found.
The new information comes from a study of the medical records of 29,507 infants, being published Thursday in The New England Journal of Medicine by researchers from Vanderbilt University and Boston University.
The study found 209 infants had been exposed to ACE inhibitors in the first three months of their mothers' pregnancy, 18 of whom had birth defects; in half, the heart was affected.
The rate of defects among infants exposed to the drugs was 2.7 times that of infants who were not. Infants whose mothers had taken other blood pressure medicines had no increased risk.
ACE inhibitors are the second-most commonly prescribed class of pharmaceuticals in the United States, with 149 million prescriptions dispensed last year. They came on the market 25 years ago.
Pregnant women and those who are planning to become pregnant should avoid the drugs, the researchers warn.
"It would be important for a pregnant woman and her health-care provider to be aware of this, so they can identify an alternative medicine to treat her hypertension," said William O. Cooper, a pediatrician at Vanderbilt Children's Hospital who headed the study.