HIV protection during pregnancy is examined
Research indicates that women are at risk for heightened HIV infection during pregnancy, but what about their partners?1 New data presented at the May 2010 Microbicides 2010 international conference indicates that men face a doubled risk for HIV if their partner is HIV-infected and pregnant.2
The 2010 meeting represents the sixth biennial gathering of the International Microbicides Conference, which gathers leading investigators, clinicians, policymakers, community advocates, and experts in global health who are working in all facets of HIV prevention and in all parts of the world.
The new study, which involved 3,321 couples in which one partner was HIV-infected and the other not, is the first to show that a man in a relationship with an HIV-positive woman has a greater chance of becoming infected while she is pregnant than when she is not.2
Even when researchers accounted for behavioral and other factors that can contribute to HIV risk, the increased risk associated with pregnancy remained for men. Scientists believe that biological changes that occur during pregnancy might make women more infectious than they would be otherwise, says Nelly Mugo, MD, MPH, a research scientist affiliated with the University of Nairobi and Kenyatta National Hospital in Nairobi and the University of Washington in Seattle. Mugo presented results of the study, conducted in Botswana, Kenya, Rwanda, South Africa, Tanzania, Uganda, and Zambia, on behalf of the Partners in Prevention HSV/HIV Transmission Study team, based out of the University of Washington's International Clinical Research Center.
To conduct the study, scientists followed for up to two years 1,085 couples in which the male was infected and 2,236 couples in which the female was infected to understand the different circumstances and determinants that might contribute to HIV risk. During this time, 823 pregnancies took place; 320 were among couples in which the male had HIV and 503 pregnancies among couples in which the female had HIV. In total, 61 women and 58 men became infected with HIV. Of the women, 17 (27.9%) acquired HIV during pregnancy, and 12 (20.7%) of the men became infected when their partner was pregnant.
In performing their analysis, scientists found that pregnancy was associated with increased risk of female-to-male and male-to-female HIV transmission. For women with an HIV- infected partner, the study found that factors other than pregnancy, such as sexual behavior, might have contributed to the increased risk. In men, however, the link between pregnancy and HIV risk was much clearer, even after taking into considering whether the men had engaged in unprotected sex or were circumcised. More research is needed to confirm whether the increased female-to-male transmission of HIV during pregnancy is due to the physiological and immunological changes that occur with pregnancy, the authors conclude.2
Gel OK for pregnancy?
Women need a method to protect themselves from HIV/AIDS at all times, including when they are pregnant.
At the May 2010 conference, researchers reported results of the first clinical trial to evaluate the safety of a vaginal microbicide in pregnant women. The study, which involved applying a single dose of tenofovir gel hours before women gave birth by Caesarean section, represents an important first step to determine whether use of a vaginal microbicide to protect against HIV during pregnancy is safe for women and their babies.3 In its pill form, tenofovir is used in one of the most widely used regimens for treating HIV. Researchers are looking at its use in preventing the disease.
"If a microbicide is found effective for preventing HIV in women, women will need to know whether it is safe for use during pregnancy and would not be harmful to their unborn child," says Richard Beigi, MD, MSc, assistant professor of obstetrics, gynecology, and reproductive sciences at the University of Pittsburgh School of Medicine. "We are committed to understanding the answers to these questions, but we must do so in step-wise fashion, with the greatest of care and in the most ethically responsible way possible."
The study was a Phase I study conducted at Magee-Womens Hospital of the University of Pittsburgh Medical Center, and is part of the Microbicide Trials Network, an HIV/AIDS clinical trials network established by the National Institute of Allergy and Infectious Diseases. To conduct the current research, scientists investigated giving a single 40 mg dose of the tenofovir gel to 16 healthy, HIV-uninfected women hours before they gave birth. Researchers looked at how the drug is absorbed during pregnancy and whether it can transfer to the fetus. They found that only small amounts of drug were absorbed into the mother's bloodstream, amniotic fluid, and umbilical cord blood after the gel was topically applied.3
What is next in the investigation? Researchers plan to conduct a larger study of tenofovir gel in pregnant and breastfeeding women.
References
- Gray RH, Li X, Kigozi G, et al. Increased risk of incident HIV during pregnancy in Rakai, Uganda: a prospective study. Lancet 2005; 366:1,182-1,188.
- Mugo N, Heffron R, Donnell D, et al. Pregnancy is associated with an increased risk for HIV transmission among African HIV-1 serodiscordant couples. Presented at the International Microbicides Conference. Pittsburgh; May 2010.
- Beigi R, Noguchi L, Macio I, et al. Maternal single-dose pharmacokinetics and placental transfer of tenofovir 1% vaginal gel among healthy term gravidas. Presented at the International Microbicides Conference. Pittsburgh; May 2010.
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