The National HIV Testing Policy states that women contemplating pregnancy or seeking antenatal care should be made aware of the benefits of diagnosis of HIV infection and management, and that there is a high risk of mother-to-child transmission which can be almost entirely eliminated with the prevention strategies which are available for both the mother and the infant.
Antenatal testing should be recommended for all women and must only be performed with the informed consent of the woman. HIV testing must be performed in the context of appropriate risk assessment and discussion. Should the mother be found to be HIV antibody positive, expert advice must be sought promptly.
The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) guidelines state that, in the absence of complications ‘all pregnant women should be recommended to have HIV screening at the first antenatal visit’ (RANZCOG, 2009). Yet Giles’3 2006 study of obstetricians’ screening practices revealed that many obstetricians do not offer antenatal tests to all women, with the most common reason being they do not believe testing is warranted. This is despite evidence that some women do not self-acknowledge risk factors, and some women diagnosed with HIV during pregnancy had no discernible risk factors (as they contracted HIV through sex with a long-term partner they believed to be HIV-negative and monogamous).
It is argued that antenatal testing is particularly useful for low HIV prevalence countries such as Australia, in which many women do not identify themselves as engaging in high-risk behaviours and are not tested for HIV. Pregnancy is a time when women are in contact with clinicians, offering an opportunity to identify a range of pre-existing unidentified infections which can be treated with major benefit to mother and infant.
While serving as a means of identifying HIV in the mother, so that she may receive optimal medical and psychological care and decrease the risk of transmission to sexual partners, the primary goal of antenatal testing for HIV is to prevent mother-to-child transmission of infection. Prevention of mother-to-child transmission of HIV is highly effective if HIV is diagnosed antenatally. The risk of transmission of HIV from a mother with HIV to her child without intervention is currently estimated at approximately 25% - 40% Recent advances in drug therapy, particularly combination antiretroviral therapy, avoidance of breastfeeding (in developed countries where this is safe), and modification of delivery practice (including the use of Caesarean section if indicated) reduce the risk of transmission to less than 2%
 in developed countries. Given the knowledge and means available to prevent mother-to-child transmission, a doctor who fails to offer antenatal testing could be held liable if the mother's HIV infection goes undiagnosed and a child is born with HIV as a result.
Informed consent prior to pregnancy testing is vital as women must not feel compelled to agree to an HIV test, and must not be coerced into an HIV test as part of a standard set of tests relating to pregnancy. Discussion of key issues prior to testing also enables discussion of any ongoing risk behaviours and prepares the mother for the possibility of an HIV-positive result.
Considerable anxiety and guilt may be associated with an HIV diagnosis during pregnancy, with special attention required to psychosocial issues and contact tracing (including matters related to previous sexual encounters and partners’ fidelity).
For more information on managing HIV-related antenatal testing issues, see: Talking about testing: pre-test and post-test discussion, in: HIV, viral hepatitis and STIs: a guide for primary care (ASHM 2014).
Australian cases of mother-to-child transmission
Australian cases of mother-to-child (vertical) HIV transmission are rare. The risk of transmission from mother to child is dramatically reduced through control of HIV in the mother and use of interventions such as drug therapy, caesarean section and bottle feeding. As a result, the prevalence of HIV infection in the antenatal population remains very low.
Between 2002 and 2011, 7 of 296 children born to diagnosed HIV-positive mothers were HIV-infected. An additional 9 children were born to mothers whose HIV infection was not diagnosed prior to the child’s birth – precluding use of interventions. Five of those 9 children were HIV infected .
 The Kirby Institute. HIV, viral hepatitis and sexually transmissible infections in Australia Annual Surveillance Report 2012. The Kirby Institute, the University of New South Wales, Sydney.
 World Health Organization. Strategic Vision. World Health Organization. Available at http://www.who.int/hiv/pub/mtct/strategic_vision.pdf. Accessed 26 October 2012.
 World Health Organization. Strategic Vision. World Health Organization. Available at http://www.who.int/hiv/pub/mtct/strategic_vision.pdf. Accessed June 21, 2012.
1Australian Government. Department of Health and Ageing: 2011 National HIV Testing Policy. Available from: http://testingportal.ashm.org.au/hiv (last accessed November 2012).
2The Royal Australian and New Zealand College of Obstetricians and Gynaecologists. College statement. Antenatal screening tests. Statement No. C-Obs 3. June 2008. Available at: http://www.ranzcog.edu.au/publications/statements/C-obs3.pdf (last accessed November 2012).
3Giles ML, Garland SM, Grover SR, Lewin SM, Hellard ME. Impact of an education campaign on management in pregnancy of women infected with a blood-borne virus. Med J Aust 2006;184:389-92.
4National Centre in HIV Epidemiology and Clinical Research. HIV/AIDS, viral hepatitis and sexually transmissible infections in Australia. Annual Surveillance Report 2010. Sydney: National Centre in HIV Epidemiology and Clinical Research, The University of New South Wales; 2008. Available at: http://www.nchecr.unsw.edu.au (last accessed November 2012).