Discussion
In this prospective study of more than 3300 African
heterosexual HIV-1-serodiscordant couples, pregnancy
was associated with increased incidence of HIV-1
acquisition in women and HIV-1 transmission from
women to men. Elevated risk of HIV-1 acquisition in
pregnant women appeared to be in part explained by
behavioral and other factors, as the relationship between
pregnancy and HIV-1 acquisition risk was not statistically
significant after controlling for sexual behavior and
other confounding variables. The finding that pregnancy
increases the risk of female-to-male HIV-1 transmission
two-fold is novel and has important public health
implications for reducing HIV-1 transmission in high
HIV-1 prevalence settings. These findings should
stimulate new strategies to strengthen family planning
and maternal health services for women with and at risk
for HIV-1 in order to reduce unwanted pregnancies and
avert HIV-1 transmission to pregnant women and from
pregnant HIV-1-infected women to their infants and
partners. In addition, our results strengthen the argument
for initiation of combination ART in HIV-1-infected
women during early pregnancy [12] to suppress maternal
HIV-1 viral load and, thereby, reduce the risk of both
perinatal and sexual transmission of HIV-1.