The transmission of HIV from an HIV-positive mother to her child during pregnancy, labour, delivery or breastfeeding is called vertical or mother-to-child transmission (MTCT). If a mother is HIV-positive during pregnancy, HIV treatment can improve her overall health and can protect an unborn baby from contracting HIV before, during delivery and after birth.

Prevention of MTCT (PMTCT) involves providing ARVs to mothers and infants during pregnancy, labour and the post-natal period, and offering life-long treatment to HIV-positive pregnant women regardless of their CD4 count.