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 (John's Hopkins University, Maryland, USA) 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 2188 HIV-negative sexually active women who were pregnant or breastfeeding and compared rates of HIV acquisition during these periods with 8473 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 sociodemographic or behavioural 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.
Professor Gray comments: "We cannot generalise 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 (University of Witwatersrand, 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."
Contact: Professor Ronald H Gray, John Hopkins University, School of Hygiene and Public Health, Dept. Population & Family Health Studies, 615 North Wolfe Street, Baltimore, MD 21205-2179, USA. T) 410 955 7818 rgray@jhsph.edu To reach Professor Gray from Oct 1- Oct 14 contact Jerry Napolitano T) 410 955 7820 jnapolit@jhsph.edu Alternative contact Dr. David Serwadda, T) 011 256 777 6809 dserwada@imul.com
Comment: Dr James A McIntyre, Perinatal HIV Research Unit, University of the Witwatersrand, PO Box 114, Diepkloof, Johannesburg 1864, South Africa. T) +27 11 989 9703 mcintyre@pixie.co.za
Journal
The Lancet