Pregnancy increases risk of acquiring HIV in both women and men

Biological changes that occur during pregnancy may make women who are HIV-positive more infectious than they would be otherwise, according to research presented Sunday at the International Microbicides Conference in Pittsburgh, Pennsylvania.

Previous studies have shown that women are at increased risk of acquiring HIV from an infected partner during pregnancy. A new study presented today at the International Microbicides Conference in Pittsburgh revealed that pregnancy also doubles mens' risk for acquiring HIV if in a relationship with an HIV-positive woman. 

Researchers studied 3,321 couples in which one partner was HIV-infected and the other was not to understand the different circumstances that may contribute to HIV risk.  The couples -- 1,085 in which the male was infected and 2,236 in which the female was infected -- were followed for up to two years. 

Even after accounting for behavioral and other factors that usually contribute to HIV risk, the increased risk associated with pregnancy remained. Biological changes that occur during pregnancy may make women more infectious than they would be otherwise, said Nelly Mugo, MD, MPH, of the University of Nairobi and Kenyatta National Hospital in Nairobi and the University of Washington in Seattle. Mugo presented the study results 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.

During the study period, 823 pregnancies took place, which allowed the researchers to look more closely at the particular risk factors for HIV that occur during pregnancy. They found that pregnancy was associated with increased risk of both female-to-male and male-to-female HIV transmission. But for women with an HIV- infected partner, 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 they had engaged in unprotected sex or were circumcised. Measures of viral load (the quantity of Human Immunodeficiency Virus) and CD4 counts of the infected partner also had no bearing. CD4, or T-cells, help protect the body from infection.