Abstract
Prior to the introduction of interventions reducing mother-to-child transmission of HIV-1 natural history data reports vertical transmission rates in the order of 25%. The risk of transmission from mother-to-child has been associated with advanced maternal HIV disease, maternal plasma HIV viral load and CD4 lymphocyte count, mode of delivery, length of rupture of membranes, prematurity and breast feeding. During the last 10–15 years the introduction of prelabour cesarean section, formula feeding and antiretroviral therapy has reduced transmission to less than 1% for pregnant women in the UK who are aware of their HIV status. Attention is now turning to the minimization of possible drug side effects for both mother and infant as women are increasingly conceiving on combination antiretroviral therapy. The evolution of current UK guidelines on the prevention of mother-to-child transmission of HIV-1 are discussed.