The findings of a recent study may quiet concerns that the babies of women who are HIV-positive during pregnancy will be more prone to birth defects if the mother takes antiretroviral drugs. Pregnant women are often urged to take antiretroviral drugs during pregnancy if they’re not already taking them; the drugs are highly effective in preventing mother-to-child transmission of the virus.

The study, led by Jeanne Sibiude, from the French Institute of Health and Medical Research’s (INSERM’s) Center for Research in Epidemiology and Population Health, examined records of children born between 1994 and 2010 to HIV-infected mothers who gave birth in 90 medical centers across France. The 13,124 babies in question were exposed to antiretroviral drugs in utero.

Sibiude’s research team used two classification systems for birth defects — the EUROCAT and the MACDP — to identify the babies who experienced defects:

  • The EUROCAT is a network of registries that documents congenital anomalies in 20 European nations. It lists about 1.5 million births in its collective registry.
  • The MACDP is the Metropolitan Atlanta (Georgia) Congenital Defects Program established by the US Centers for Disease Control and Prevention in 1967 to track birth defects in the city’s metropolitan area.

The mothers of the babies in the study had taken at least one of the following antiretroviral drugs during pregnancy:

  • Abacavir
  • Efavirenz
  • Lopinavir
  • Nevirapine
  • Ritonavir
  • Stavudine
  • Tenofovir
  • Zidovudine

The INSERM research team did not have data that documented pregnancy terminations, stillbirths, the mother’s use of alcohol or tobacco during pregnancy, or any other medications she was taking along with the antiretrovirals.

The antiretrovirals were effective in preventing transmission of the virus to the babies and the number of birth defects recorded was very small. Birth defects were associated with only two of the eight drugs under study. Classification systems seemed to make a difference, too:

  • 0.7% increased risk of neurological birth defects after exposure to efavirenz but only when the MACDP classification system was applied
  • 1.2% increased risk of heart defects when zidovudine was taken; results were the same using both classification systems.

Babies exposed to the remaining six antiretroviral drugs during gestation exhibited no signs of birth defects regardless of which classification system was used.

The researchers conclude: “Whatever the impact that some (antiretroviral) drugs may have on birth defects, it is surpassed by the major role of (antiretroviral therapy) in the successful prevention of mother-to-child transmission of HIV.”

Source: Sibiude, Jeanne, et al. “Association Between Prenatal Exposure to Antiretroviral Therapy and Birth Defects: An Analysis of the French Perinatal Cohort Study (ANRS CO1/CO11).” PLOS / Medicine. PLOS. Apr 29, 2014. Web. May 14, 2014.