In the Rakai district of Uganda pregnant women have higher risk of acquiring HIV than women who are not pregnant, according to a study published in this week's issue of The Lancet. The researchers controlled for behavioral factors that could affect HIV acquisition and still found this trend; suggesting that biology rather than behavior is responsible. They believe that hormonal changes during pregnancy could make women more susceptible to HIV infection.
An observational study in Malawi found that HIV acquisition is substantially higher during pregnancy than after giving birth. Another study in Rakai, Uganda suggested similar trends. However, neither of these other studies adjusted for factors that can affect HIV risk.
Ronald Gray, of Johns Hopkins University in Maryland, and colleagues assessed the incidence rate of HIV during pregnancy and lactation, and compared this to the incidence rate of HIV in women who were not pregnant or breastfeeding. They assessed 2,188 HIV-negative sexually active women who were pregnant or breastfeeding and compared rates of HIV acquisition during these periods with 8,473 non-pregnant and non-lactating women. The investigators found that the HIV incidence rate was higher during intervals of pregnancy than during breastfeeding, or exposure intervals with no pregnancy or lactation. This excess risk remained significant even after adjustment for socio-demographic or behavioral factors that might increase HIV risk. HIV incidence rates were 2·3 per 100 person years during pregnancy, 1·3 per 100 person years during breastfeeding, and 1·1 per 100 person years in the women who were not pregnant or breastfeeding.
Gray comments, We cannot generalize our findings beyond the Rakai setting and it would be important for other investigators to verify our results. However, if women are at increased risk of HIV acquisition during pregnancy, our findings represent a public-health problem, both for the mother and possibly her unborn infant. We believe that it would be prudent to warn women of this potential risk of HIV acquisition during pregnancy and promote safe sex or sexual abstinence where feasible.
In an accompanying comment, James McIntyre, of the University of Witwatersrand in Johannesburg, South Africa, states, The authors have been able to control for sexual behavior to a greater extent than previous reports, and they show little effect of behavioral factors on the increased risk of HIV acquisition in pregnant women suggesting that biological changes in pregnancy have an important role.
Source: The Lancet