Research suggests Truvada (tenofovir/emtricitabine) as pre-exposure prophylaxis may be safe for the pregnancies of HIV-negative women when taken until just after conception, although a definite answer on the matter is still out of reach. Publishing their findings in JAMA, investigators in the Partners PrEP Study researched 1,785 mixed-HIV status heterosexual couples in which the woman was HIV negative, randomizing the women to receive daily oral tenofovir (598 women), daily Truvada (566 women) or a placebo (621 women).

The study began in June 2008. After PrEP proved effective at reducing the risk of HIV acquisition in 2011, the placebo group was discontinued. The participants were tested monthly for pregnancy, and they discontinued PrEP if they became pregnant.

There were 431 pregnancies during the trial. The pregnancy incidence per 100 person-years for the three respective groups was 10 in the placebo group, 11.9 in the tenofovir group and 8.8 for those who received Truvada. Before the placebo group was terminated, the rate of pregnancy loss among the groups was 42.5 percent in the Truvada group, 32.3 percent in the placebo group and 27.7 percent for those who just took tenofovir. After the discontinuation of the placebo group, the rate of pregnancy loss was 37.5 percent for the Truvada group and 36.7 percent for those taking just tenofovir. However, none of these differences in pregnancy incidence or loss were statistically significant, meaning they could have occurred by chance. Nor was there any statistically significant difference in birth outcomes or infant growth.

The authors of the paper caution that because PrEP was discontinued when the pregnancies were detected, and because the statistical analysis for the difference in birth outcomes resulted in wide estimate ranges, the door is open for actual differences between the three groups; as a result, this study cannot make any “definitive statements about the safety of PrEP in the periconception period.” (Periconception is the period before and shortly after conception.)

To read the JAMA article, click here.