WEDNESDAY, June 12, 2002 (HealthDayNews) -- Pregnant women taking drugs to control HIV can at least take heart in one matter: The therapy isn't likely to cause problems for their unborn babies.
A new study of more than 3,200 women with the AIDS virus has found that even the most potent combinations of antiviral drugs don't seem to harm fetal development. Babies born to women taking these regimens are at no greater risk of stillbirth, prematurity, or poor scores on an initial gauge of newborn vitality than are babies of infected mothers not on the medications.
The only trouble spot, the researchers said, is a somewhat increased risk of very low birth weight among babies born to mothers on drug combinations that include protease inhibitors. But why the addition of this powerful therapy might lead to lightweight infants isn't clear, and further studies are needed to see if the association is real, the researchers said.
Dr. Heather Watts, a childhood AIDS expert at the National Institute of Child Health and Human Development, which helped fund the study, said the results are good news for women with HIV.
"The combination therapy seems to be best for reducing transmission to infants and also for maternal long-term health," Watts said.
A report on the findings appears in tomorrow's issue of the New England Journal of Medicine.
World health officials estimate that last year, 800,000 children under age 15 were newly infected with HIV, another 2.7 million already had the virus, and 580,000 others died of AIDS. Most children who contract HIV get it from their mothers, either in the womb or at birth. The virus can also pass from mother to infant through breast milk, although this form of transmission is rare in the United States because women with HIV are discouraged from nursing.
Antiviral drugs like AZT can prevent the spread of HIV from mother to baby. But two studies in the late 1990s seemed to show a strong link between these therapies -- and particularly combination regimens -- and the risk of premature birth.
In the new work, a team of researchers from government and academia sought to verify that connection by analyzing seven previous studies looking at the impact of HIV treatments on newborns.
The researchers included 2,123 HIV-positive pregnant women who were taking at least one drug to control their infection and 1,143 others who took none. The study did not include women without HIV, and some evidence suggests that those carrying the virus have a higher risk of pregnancy complications. That seems to be the result, at least in this country, of their greater use of drugs, alcohol and tobacco than other women, and not of HIV itself, Watts said.
After accounting for factors like use of illegal drugs or alcohol, smoking, and immune system strength, the researchers found no evidence that either single drug treatments or multi-drug treatments were more harmful to newborns than none at all.
Babies born to these women had essentially the same odds of being premature, being underweight, being stillborn, or of having low Apgar scores, a measure of newborn health that stands for activity, pulse, grimace (a sign of reflex strength), appearance (of skin color), and respiration.
The researchers did find that 5 percent of women whose treatment included protease inhibitors had very underweight babies -- less than about 3.3 pounds -- compared with just 2 percent of those not getting the drugs in a combination regimen.
The difference may reflect the possibility that women who received protease inhibitors were sicker and had more advanced disease than those on other HIV therapies, the researchers said.
"Any small increase in the risk of low birth weight is likely to be outweighed by the substantial benefits of treatment with protease inhibitors for both the mother and the infant," they wrote.
Dr. Katherine Luzuriaga, a specialist in pediatric AIDS at the University of Massachusetts Medical School in Worcester, called the findings "noteworthy," and said they should reassure doctors and pregnant women with HIV.
But Luzuriaga said it remains to be seen whether the antiviral drugs have any long-term effects on the children exposed to them in the womb.
"The only way that we are going to know about the long-term safety of these particular drug regimens is to continue to follow these children up to be sure that we're not missing anything," she said.
What To Do
For more on AIDS and children, try the Elizabeth Glaser Pediatrics AIDS Foundation. You can also check out the Centers for Disease Control and Prevention or UNAIDS.
