Objective: to review the literature on early vertical transmission of the HIV virus and its possible prevention. Method: databases were searched using the keywords HIV, AIDS, HIV transmission, vertical transmission, HIV pregnancy, HIV newborn, AIDS paediatric, HIV paediatric, HIV maternal, maternal immunity, HIV diagnosis, Two hundred and twenty-nine articles were generated and 41 were used in the review. Findings: factors which increase the risk of vertical transmission are: maternal drug misuse; maternal infection; malnutrition; and HIV viraemia. There are gaps in knowledge about the mechanisms and rates of transmission indicating further research is needed. Key conclusions: prevention of early vertical transmission is very important; researchers need to standardise their research criteria when carrying out research so that conclusions are comparable. Implications for midwifery practice: to promote the health of women and their partners must be educated prior to conception and during pregnancy on family planning and healthy living; HIV positive women need counselling and support, and midwives must consider all unscreened pregnant women to be HIV positive.