By Sally Robertson, BSc
The transmission of HIV from mother to child during pregnancy, childbirth, or breastfeeding is referred to as perinatal transmission. This is the most common way in which infants become infected with HIV.
A woman who is planning a pregnancy or who is already pregnant should be screened for HIV and her partner should also be tested. The Centers for Disease Control and Prevention (CDC) advises that women also receive a further test during the third trimester of their pregnancy if they continue to engage in behavior that increases the likelihood of them transmitting HIV.
In addition, the CDC says that women who go into labor before they have been tested should be screened in the delivery room. The test is rapid, producing results in less than an hour and, if positive, doctors can work with the mother to prevent HIV being transmitted to the baby during delivery.
If a woman is diagnosed with HIV either while planning to become pregnant or during pregnancy, she can be prescribed antiretroviral therapy (ART), which significantly reduces the risk of mother-to-child transmission. If a pregnant woman with HIV is not treated, the risk of her baby being born with the virus is 25%.
The aim of HIV care during pregnancy is to ensure the mother remains as healthy as possible and to significantly reduce the likelihood of HIV being passed onto the baby before, during, or after birth.
Treatments are most effective when they are started as early on in the pregnancy as possible, although beginning treatment at a later pregnancy stage, during labor, or even during delivery can be greatly beneficial.
The goal of ART is to lower the amount of HIV in the woman’s body to a level that is undetectable (referred to as undetectable viral load). This lowers the risk of her passing the virus onto her baby during pregnancy or childbirth.
Many HIV medicines are available that can be safely used during pregnancy. Healthcare providers carefully discuss with the patient the benefits and risks of taking specific HIV drugs before deciding on which HIV regimen to use.
When recommending which medicines to take, healthcare providers consider what is already known about the use of certain HIV drugs during pregnancy and the risk of any side effects that could be harmful to the mother or baby.
Other factors that are taken into consideration include the following:
- The woman’s medical history including any use of HIV drugs in the past
- Any changes in the body related to pregnancy that could impact on the body’s ability to process the drugs. Such changes may mean the dosage needs altering throughout the pregnancy
- The possible interactions between HIV drugs and any other drugs the mother may already be taking
- The woman’s ability to follow the instructions for taking the medicines
- The results of drug-resistance testing, which determines whether there are any HIV drugs that will not be effective
The preferred drug regimen for women who have never taken HIV drugs before should include two nucleoside reverse transcriptase inhibitors. At least one of these should be from the following drugs because these can move across the placenta easily:
In addition, the regimen should include a non-nucleoside reverse transcriptase inhibitor, an integrase strand transfer inhibitor or a protease inhibitor with ritonavir. A woman who is already undergoing ART should continue taking her medicine. However, her drug regimen may be revised due to the bodily changes during pregnancy that can affect how the medicine is processed.
Pregnant women can discuss with their healthcare providers how to proceed when it comes to delivery. If a woman’s viral load is high or not known, a cesarean section at 38 weeks is recommended to lower the likelihood of transmission by avoiding labor and the risk of membrane rupture. However, every woman’s situation is considered on an individual basis and any of the decisions made about HIV drug regimens or childbirth are arrived at jointly by the woman and her healthcare provider.
Reviewed by Susha Cheriyedath, MSc
Last Updated: Jun 22, 2016