PrEP use among pregnant women in Kenya: no adverse effects found

The study found no difference between women who did and did not use pre exposure prophylaxis (PrEP) while pregnant in regards to premature birth, infant age and weight at birth, infant growth at six weeks and birth defects.

In the last decade, prevention of mother‐to‐child HIV transmission (PMTCT) programmes have significantly increased access to long-term antiretroviral treatment (ART) for women living with HIV who become pregnant, greatly reducing rates of vertical transmission during pregnancy, childbirth and breastfeeding. However, a gap remains in relation to women who acquire HIV while pregnant or breastfeeding.

Current evidence suggests PrEP is safe to use during pregnancy and it is now recommended by the World Health Organization (WHO) for pregnant and breastfeeding women at high risk of HIV to prevent both themselves and their infants from acquiring the virus. However, the health body continues to advocate for further evaluation of PrEP use among this population group after two studies reported an association between poor infant growth after one year and the use of tenofovir (TDF)‐based ART regimens, the primary active ingredient in PrEP, among pregnant women.

To add to the evidence base, data on PrEP use, pregnancy, birth and infant outcomes was collected among 1,530 mother‐infant pairs receiving postnatal services at 16 maternal and child health clinics in Kisumu County, Western Kenya, all of which were participating in a PrEP implementation trial for adolescent girls and young women.

Around 205 women had taken PrEP during pregnancy and 1,325 had not. The median age of women in both groups was 24 and 85% were married. Women who used PrEP during pregnancy were significantly more likely than none PrEP users to have a partner with an unknown or HIV‐positive status (56% vs. 27%), have had sex without a condom in the past six months (97% vs. 92%), experienced intimate partner violence (6% vs. 1%) and tested positive for syphilis (1% vs. 0.3%), all factors that increase vulnerability to HIV. The majority of PrEP users began taking PrEP in their second trimester and had been on it for more than a month.

No major differences were found between PrEP-exposed and unexposed infants in terms of premature birth and low birthweight. In both groups, babies had a mean weight of 3.3kg and were born at 38.5 weeks.

No physical birth defects occurred among infants born to pregnant women using PrEP, while five babies who had not been exposed to PrEP were born with physical abnormalities. However, the small sample size means no conclusion can be drawn from the discrepancy between groups.

At six weeks of birth, infants in both groups had similar growth levels. At this point, the mean weight for both groups was around 5k.g. In addition, no differences were found between groups in the proportion of infants categorised as underweight (3% in both groups), stunted (8% vs. 9%) or wasted (6% vs. 8%).

Pregnancy and infant growth outcomes were similar whether women initiated PrEP in the first, second or third trimesters There was also no difference found when purely analysing PrEP use among adolescent girls and young women (15-24 years) or when adjusting for partner HIV status.

While this study did not find evidence of compromised infant growth in relation to PrEP use, it is important to note that it only analysed infant growth data up to six-weeks and was not able to assess the longer-term impact of PrEP use. Future analyses should consider collecting infant growth data at a later time, particularly to better examine the impact on infant growth when exposure to TDF has occurred during gestation. However, the findings from this study provide further encouraging evidence of the safety of PrEP for pregnant women and their infants.