First trial of a microbicide in pregnant women

M2010 runs May 22 to 25 in Pittsburgh, David L. Nearly 1,000 participants from 47 countries attended the meeting to hear the latest developments in research on HIV prevention. Summary of two studies related to pregnancy are provided below.70-90 % of all HIV infections in women are acquired through heterosexual intercourse and women are twice as likely as their male partners of HIV during sex, due in part to biological factors that make them more sensitive. Many women remain sexually active during pregnancy. Although correct and consistent use of condoms has been shown to prevent HIV infection, women are often unable or unwilling to negotiate condom use with male partners. And for many women, especially those who wish to become pregnant, abstinence is not an option that can be conceived. Microbicides – substances intended to be applied topically to the rectum or vagina – are under active investigation as a method for women to use to protect themselves against HIV

The results of the first study of a vaginal microbicide in pregnant women tested found that small amounts of drug are absorbed into the blood fluid, amniotic fluid and umbilical cord blood. The results confirm continuing with other studies of tenofovir gel in pregnant women, said Richard Beigi, MD, MSc. At the University of Pittsburgh and Magee-Womens Hospital of UPMC, who led the study for the Microbicide Trials Network.

Although several studies have shown that pregnant women are at increased risk of contracting HIV from an infected partner, a new study has found pregnancy is a time when men are most at risk – the risk doubled in reality. The study, which involved 3,321 couples in which one partner is infected with HIV and the other not, is the first to show a man in a relationship with an HIV-positive woman has a better chance of being infected while she is pregnant when it is not.

Even allowing for behavioral and other factors that usually contribute to the risk of HIV, the increased risk associated with pregnancy remained. Biological changes that occur during pregnancy can make women more infectious than they would otherwise, explains Nelly Mugo, MD, MPH, University of Nairobi and Kenyatta National Hospital in Nairobi and the University of Washington in Seattle, who presented the results the study on behalf of the Partners in Prevention HSV / HIV Transmission Study Team. The study was conducted in Botswana, Kenya, Rwanda, South Africa, Tanzania, Uganda and Zambia.

Pregnancy is a time when they may be more sensitive. Since no information was available on whether using a microbicide candidate is safe during pregnancy, women who participate in clinical trials should be used, and whether pregnant women should stop using the product-time study in which protection may need more. In this study, a gel containing a single dose of tenofovir gel was applied in 16 healthy HIV-negative women about two hours before she gave birth by elective caesarean section. The researchers collected samples of maternal blood before and 24 hours after the gel has been applied and took samples of amniotic fluid surrounding the baby, the umbilical cord blood, placental tissue and uterine tissue. In addition to finding very low levels of drugs, the researchers also reported serious side effects caused by frost in the two mothers or their babies. Based on these results, the researchers now plan to conduct a larger study of tenofovir gel in pregnant and lactating women at a time.

Study co-authors include Marc Melcher, MD, Jin-Yon Kim, MD, Julie Yabu, MD, Jane Tan, MD, John Scandling, MD, and Stephan Busque, MD .

The researchers followed for two years at most 1 085 couples where the man was infected and 2,236 couples where the woman was infected to understand the different circumstances and factors that may contribute to risk of HIV infection. Meanwhile, 823 pregnancies occurred, which allowed researchers to examine more closely the particular risk factors for HIV that occur during pregnancy and no. In their analysis, they found that pregnancy was associated with an increased risk of transmission of two women, men and women and women with HIV. But for women with a partner infected with HIV, the study found that factors other than pregnancy also likely contributed to this increased risk, such as sexual behavior. In men, however, the link between pregnancy and HIV risk was much clearer, even after considering whether or not had unprotected sex or have been circumcised.

Increase in female to male transmission of HIV during pregnancy may be due to physiological and immunological changes that occur with pregnancy, the authors conclude, but more research is needed to confirm this hypothesis.