Reuters 26 Dec. 2001

HIV-infected women who take certain combinations of medications in their first trimester of pregnancy may increase the risk of having a child with birth defects, a small study suggests.

In particular, women who took a drug to ward off Pneumocystis carinii pneumonia (PCP)--a common and often life-threatening infection seen in AIDS patients--in combination with antiretroviral drugs early in pregnancy were more likely to have a baby with birth defects.

However, taking either type of drug alone in early pregnancy did not seem to be a problem. And taking antiretroviral drugs later in pregnancy is known to dramatically decrease the chances that a mother will pass HIV to her baby. Worldwide surveillance to date has shown no excess risk of birth defects in infants exposed to such drugs during pregnancy.

The finding is reported in the December issue of the journal Sexually Transmitted Infections.

In the study, Dr. Graham Taylor from Imperial College in London, UK and colleagues evaluated the risk of birth defects in infants of 195 HIV-infected mothers.

Overall, nine children (4.6%) were born with abnormalities, the authors report. None of the 34 infants exposed to either antiretroviral drugs alone or PCP-preventing drugs alone during the first trimester had birth defects. In contrast, three of 13 (23.1%) children exposed to both therapies had birth defects, the report indicates.

"Although the numbers are small, they had a sevenfold increased risk of birth defects compared with infants not exposed to any drugs during the first trimester," the authors write.

"These findings, if confirmed, have important implications for preconceptual counseling and the therapeutic choices of women of childbearing age," they conclude.

Taylor told Reuters Health that physicians should take care "to regularly review the needs of therapy before women become pregnant and to ensure that women with HIV who wish to become pregnant, especially those who need to take PCP prophylaxis, take folic acid supplements."

Drugs used to combat PCP are known as folate antagonists, meaning they deplete folate--the form of folic acid found in the blood--in the body. Folic acid has been found to help prevent birth defects when taken by women before and during early pregnancy.

The findings "suggest that the need for PCP prophylaxis should be regularly reviewed in all women of child-bearing potential," Taylor added.

Source: Sexually Transmitted Infections 2001;77:441-443.