PrEP during pregnancy: safety evidence ‘reassuring’ but gaps remain
Research on PrEP safety for pregnant women and their babies finds no adverse effects – but knowledge gaps remain.
The findings, which come from a systematic review published in the Journal of the International AIDS Society, examined five completed and nine planned or ongoing studies. None of the completed studies found any PrEP-related adverse outcomes in pregnancy or post-birth. However, the review identified several research gaps that will need to be address if PrEP is to be scaled up for pregnant women.
The World Health Organization recommends offering PrEP to pregnant and breastfeeding women at substantial risk of HIV infection but many countries are yet to follow this guidance. This is despite evidence that the risk of acquiring HIV more than doubles for women when they are pregnant or have just given birth.
The nine ongoing or planned studies analysed by the review are being conducted in Kenya, Malawi, South Africa, Uganda, the United States and Zimbabwe and will be completed by 2022. Together they will provide data on an additional 6,200 pregnant women taking PrEP. Although this will expand the data on PrEP safety in pregnancy six-fold, addressing key research gaps will be vital to convince a number of countries to provide PrEP for pregnant women. It has been reported that the desire for additional safety evidence has hindered PrEP implementation among pregnant women in South Africa, Malawi and Zambia, for instance.
The five completed studies included a total of 1,000 women in Kenya, Uganda, Zimbabwe and South Africa and were conducted between 2014 and 2018. Four of these studies found no differences in pregnancy or infant outcomes among women taking PrEP compared to women who were not. One study found that PrEP-exposed infants were smaller in length at four weeks but no difference after a year.
The analysis identified four major research gaps. The first relates to PrEP exposure levels, including the drug levels needed to protect women and infants from acquiring HIV. Pregnancy can affect drug pharmacokinetics (the time the body takes to absorb, distribute, metabolise and excrete a drug), but to date only one small study has examined this issue. This found pregnancy can lower PrEP levels by between 45–58%, and more so as the pregnancy progresses. It is currently unclear whether lower PrEP levels during pregnancy have implications for preventing HIV among pregnant women and infants, yet only two studies are due to investigate this issue.
Another important gap relates to post-birth complications. Although all current or planned studies will evaluate outcomes including gestational age at birth, birth length, birth weight, pregnancy loss and congenital abnormalities, most will only include women who begin taking PrEP during pregnancy. This means data on the effects of taking PrEP before conceiving or during the early stages of pregnancy will be limited. In addition, none of the studies analysed are due to evaluate neurocognitive outcomes among PrEP-exposed infants.
The review also highlighted the need for studies to examine longer‐term outcomes for children born to women who are on PrEP, beyond infancy and into early childhood. Few studies analysed by the review are due to follow infants after they reach their first birthday.
A need to examine a broader range of health outcomes among pregnant women, such as bone health, was also identified. An examination of the connection between birth complications and sexually transmitted infections among pregnant women on PrEP was also suggested as a key area for analysis.