A pregnant woman who is HIV-positive can pass the virus onto her baby during pregnancy, during childbirth or through breastfeeding. This mother-to-child transmission, also referred to as perinatal transmission, is the most common route of HIV infection among children.

When a woman is diagnosed with HIV during pregnancy, treatment with a combination of antiretroviral medications can reduce the risk of this transmission to less than 1%.

Treatment is most effective if started as early on as possible during the pregnancy, although beginning treatment at a later stage or even during delivery can be greatly beneficial.

Medication

HIV medications are used at the following times:

• During pregnancy HIV-positive women receive antiretroviral therapy (ART) which includes a combination of at least three drugs

• During labor and delivery, oral medications are continued and she is also administered intravenous zidovudine (also called AZT)

• After birth, babies are administered AZT for six weeks. In addition to AZT, babies born to mothers who did not receive HIV drugs during pregnancy may also be given other HIV drugs.

HIV medications work by reducing the amount of HIV (viral load) present in the mother’s body, ideally to an undetectable level.

This reduces the chance of the mother passing the virus on to her baby during pregnancy or birth. Some of these drugs can also cross the placenta and reach the body of the unborn baby, which can help to protect it from infection.

This is very important during delivery when the baby is at risk of exposure to any virus present in the mother’s blood or other bodily fluids.

Medication Risks

When advising on HIV drug regimens for use during pregnancy, healthcare providers consider the benefits and risks of the various medications available including the short- and long-term effects on babies born to HIV-positive mothers.

Although research has not shown any clear association between the use of these medicines and birth defects, some drugs have raised concerns.

In the US, women taking these drugs during their pregnancy are advised to enrol in the Antiretroviral Pregnancy Registry, which monitors prenatal exposure to these medications in order to identify any potential increased risk of birth defects related to their use.

Breastfeeding

HIV is present in breast milk. However, advances in the use of ART have meant that HIV-positive women no longer need to avoid breastfeeding.

In 2011, the British HIV Association updated their Position Paper to state that if an HIV-positive mother has already been receiving triple ART and was repeatedly shown to have an undetectable viral load during delivery, then she may, after thorough consideration, proceed with breastfeeding during the first six month’s of the child’s life.

However, if she does choose this option, she should breastfeed exclusively because mixing the milk with other foods raises the risk of HIV being passed onto the baby.

The guidelines for HIV-positive mothers who choose to breastfeed recommend the following:

Mothers should receive:

• Support in their decision to breastfeed exclusively

• Triple ART for more than 13 weeks prior to delivery and also until one week after weaning

• Monitoring to ensure an undetectable viral load (of less than 50 copies per mm3)

• Follow-up checks on a regular basis to check medication adherence

• Rapid treatment of any problems that arise with breasts or breastfeeding

Infants should receive:

• Preventative treatment with ART for 4 to 6 weeks after birth

• Regular checking of HIV status

• Reconsideration of these measures in the light of any new findings