Women planning to become pregnant are cautioned to be careful with a popular class of high blood pressure drugs, according to a study in the New England Journal of Medicine Thursday.

The caution comes from researchers who have found the drugs may cause birth defects to the foetus.

The drugs, called ACE inhibitors, were already known to be dangerous to the foetus if taken later in pregnancy. The study has showed that defects can result from using the drugs also during the first three months.

Professor Garry Jennings, director of the Baker Heart Research Institute, said women should stop taking such drugs before trying to get pregnant.

Source: Xinhua/agencies