Fertility transition and HIV epidemics are currently running parallel in some sub-Saharan African populations. Interactions between the two at the individual and population levels could accentuate or moderate the resulting demographic trends. We review a number of mechanisms
through which an HIV epidemic and responses to it can affect birth rates, through the biological and behavioural proximate determinants. Uninfected as well as infected people can be affected and many of the changes could have unintended consequences for fertility at the individual level.
Results from a small-scale in-depth study in two rural areas of Zimbabwe are reviewed. These indicate that the local HIV epidemic has begun to influence the proximate determinants of fertility. If observed trends persist, a modest acceleration in the recent decline in birth rates seems plausible.