Pre-exposure Prophylaxis (PrEP) antiretroviral therapy in breast milk poses low risk to infants

Pre-exposure Prophylaxis (PrEP) antiretroviral therapy in breast milk poses low risk to infants

Research shows exposure to antiretroviral therapy (ARV) among HIV negative persons, also known as Pre-exposure Prophylaxis (PrEP), significantly reduces the risk of HIV infection. However there has been limited understanding about the safety of using PrEP during pregnancy and while breast-feeding.

Adolescents and young women in sub-Saharan Africa are at an elevated risk of HIV infection. During pregnancy and the early postpartum period, the risk of HIV infection nearly doubles. There is also high risk of HIV transmission between mother and infant while breast-feeding.

Evidence suggests that PrEP treatment using the drugs emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF) is effective at reducing the risk of HIV acquisition through sexual contact. However, pregnant and breast-feeding women have been excluded from past clinical trials due to concerns about risk, leaving many unanswered questions around the safety and efficacy of PrEP for these women and breast-feeding infants.

A new PLOS Medicine study by Kenneth K. Mugwanya of the University of Washington and colleagues sought to resolve these unknown factors by measuring FTC-TDF PrEP concentrations in breast milk and subsequent infant exposure.

Doctors at two clinical sites in Kenya and Uganda dispensed oral FTC-TDF PrEP to 50 HIV negative mothers and breast-feeding infants for 10 consecutive days. The researchers then collected blood and breast milk samples from the mothers after the seventh and 10th doses, and one blood sample was collected from the infants seven days into the trial.

The results revealed low drug concentrations in the breast milk and the infants’ blood, and both mother and infant tolerated FTC-TDF PrEP well with minimal side effects. Drug concentrations in breast milk and infant blood plasma were substantially lower than the daily pediatric doses recommended for breast-feeding infants to treat infant HIV and prevent transmission from a mother who is HIV positive.

The researchers concluded that mothers can safely take PrEP during breast-feeding with low risk to infants. In an accompanying editorial, Lynne Mofenson at the Elizabeth Glaser Pediatric AIDS Foundation argued for the broad and swift implementation of FTC-TDF distribution among pregnant and breast-feeding women, given the safety and efficacy of the treatment for preventing HIV in both mothers and infants.

Related Articles:

Mugwanya KK, Hendrix CW, Mugo NR, Marzinke M, Katabira ET, Ngure K, et al. (2016) Pre-exposure Prophylaxis Use by Breastfeeding HIV-Uninfected Women: A Prospective Short-Term Study of Antiretroviral Excretion in Breast Milk and Infant Absorption. PLoS Med 13(9): e1002132. doi:10.1371/journal.pmed.1002132

Mofenson LM (2016) Tenofovir Pre-exposure Prophylaxis for Pregnant and Breastfeeding Women at Risk of HIV Infection: The Time is Now. PLoS Med 13(9): e1002133. doi:10.1371/journal.pmed.1002133

Image Credit: George Ndagu, courtesy of USAID (MCSP)


Sara Kassabian is the Social Media Programs Manager at PLOS, where she spends a lot of time writing and editing content for different digital platforms, as well as managing social media strategy and editorial operations for the PLOS Blogs Network ( Sara is a former journalist who completed her MS in Global Health at the University of California San Francisco (UCSF), where her research focused on the prioritization of maternal and newborn health in global health policy. She can be reached by email at and on Twitter @sarakassabian.

Leave a Reply

Your email address will not be published. Required fields are marked *