In today's Health Matters, women with high blood pressure during the early stages of pregnancy may have a greater risk of having babies with birth defects.

Researchers studied nearly a half million mother-infant pairs. Analysis showed women who used a type of drug to company hypertension, known as an ace inhibitor during their first trimester, were more likely to have a baby with a birth defect.

A similar risk was found among women who used other hypertension drugs; as well as those with high blood pressure who did not take any medication.

Study authors say findings suggest it's the hypertension that harms the baby, not the drugs taken.

Their research appears in the 'British Medical Journal.'