The World Health Organisation advises HIV-positive pregnant and breastfeading women to use anti-retroviral drugs to help prevent a virus transmission.
The organisation has this week issued new recommendations on the treatment of HIV/AIDS based on the latest scientific data.
A WHO representative in Papua New Guinea, Dr Eigil Sorensen, says the guidelines include earlier treatment of adolescents and adults, and more patient-friendly antiretroviral drugs.
Mr Sorensen says there are also changes regarding expecting and new mothers.
"This is a change related to the pregancy that it was earlier recommended to start at the third trimester, but the new recommendation is to start treatment from the 14th week in the pregnancy and continue until the end of the breastfeeding period, until the child is 12 months [old]."
Eigil Sorensen says the drugs will make a mother to child transmission of the virus less likely and will improve the survival chances of the newborn.