All pregnant women, particularly those from countries with a high HIV prevalence, should be tested for HIV early in their pregnancy.
Research reported in the latest issue of the Medical Journal of Australia
shows that mother-to-child transmission rates have been significantly reduced through interventions where HIV infection is diagnosed antenatally.
The research examined perinatal exposure to HIV among children born in Australia between 1982 and 2006.
Co-author Professor John Kaldor, Deputy Director and Professor of Epidemiology at the National Centre in HIV Epidemiology and Clinical Research, Sydney, said the research showed a substantial increase in the reported rate of perinatal HIV exposure over the period, from 2.3 to 8.3 per 100,000 live births, partly due to increased testing of pregnant women.
"The increase in rates was largely related to HIV infection in women from countries with a high prevalence, such as sub-Saharan Africa, but not among Australian-born women," Professor Kaldor said.
"However, it is known that use of three interventions - antiretroviral therapy during pregnancy, elective caesarean and avoidance of breastfeeding - can reduce the risk of transmitting the virus to babies.
"Among children whose mothers were diagnosed antenatally, mother-to-child transmission declined from 25% in 1987-1990 to 5% in 2003-2006, and to 1% among those whose mothers used at least two interventions.
Mother-to-child transmission remained high among children whose mothers' HIV infection status was not known during pregnancy (45%) and among those diagnosed antenatally who used no interventions (47%).
An earlier study showed that use of antenatal HIV antibody testing has steadily increased in Australia to around 60% of pregnant women.
But HIV infection remained undiagnosed during pregnancy for some women, resulting in a substantial proportion of their babies becoming infected. National policy was revised in 2006 and now recommends that antenatal HIV testing be offered to all pregnant women.