Is PrEP Safe for Pregnant Women with HIV-positive Partners?
When Caroline Watson headed to the doctor after getting a positive pregnancy test in 2012, she had all the usual tests, and then her doctors asked her something new: Would she like to take the HIV drug Truvada to reduce the chance she’d contract HIV while she was pregnant? Watson was HIV-negative, but her husband, Deon, was HIV-positive.
Finding a way to protect women from HIV while they are pregnant may be especially important because some research indicates that being pregnant may make women more susceptible to HIV infection. The mechanism for this risk is yet unknown, but the combination of increased risk and the risk that a woman newly infected could pass HIV on to her fetus makes finding effective solutions critical.
Watson’s doctors told her that taking Truvada could add another layer of protection to prevent her, and her unborn baby, from being infected. But Watson demurred when she heard that there had been very little research done on the method known as pre-exposure prophylaxis (PrEP) during pregnancy.
“I didn’t know what the risk was going to be for my baby, so they continued to offer it and I continued to decline,” Watson explained.
Today, pregnant women have a little more information on which to make their decision on PrEP. Findings from the Partners PrEP study, released this summer in the Journal of the American Medical Association (JAMA) suggest that Truvada used for PrEP during pregnancy isn’t harmful to either mothers or their babies.
“We don’t think we need to be concerned about HIV-negative women taking Truvada during pregnancy,” said Renee Heffron, assistant professor of Global Health at the University of Washington, a principle investigator in the Partners PrEP trial and co-author of the JAMA paper. “The results are not definitive, but it’s not making us feel concerned.”
Similar to Placebo
The Partners PrEP study, conducted in Uganda and Kenya between 2008 and 2013, is the first of its kind. Of the 4,737 total heterosexual couples, 1,785 consisted of couples where the man had HIV and the woman was HIV-negative. That latter group was the one reported on in the JAMA paper. Couples were randomized into three groups: in one, women received Truvada as PrEP; in another, women received tenofovir, one component of Truvada; in the third, women received a placebo. When PrEP’s effectiveness was demonstrated in 2011, women receiving placebo were re-randomized to receive either Truvada or tenofovir. Of those couples, 431 HIV-negative women got pregnant during the course of the study. Women were tested for pregnancy every month and discontinued from study medications if they became pregnant.
The Partners PrEP study results published this summer found that women who used PrEP in the early weeks of their pregnancy experienced pregnancy loss and pre-term birth at similar rates, whether they were on PrEP or placebo, and that their children were born with similar levels of birth defects and developed similarly in their first year of life whether the mother had taken PrEP or placebo.
In other words, PrEP appears safe to take in early pregnancy.
The results weren’t surprising to Heffron, who sited the Antiretroviral Pregnancy Registry, which logs data for all women on antiretrovirals during pregnancy. The registry, Heffron said, shows no evidence that Truvada is detrimental for pregnant women who use it to treat HIV infection or hepatitis B infection. “What we really lacked was data from HIV-negative women,” Heffron said.
And while these results from the Partners PrEP study do start to fill in a missing piece of the puzzle, the results are by no means definitive. For one thing, since women discontinued PrEP once their pregnancy was discovered, we don’t know about the safety of PrEP throughout pregnancy. For another thing, the rates of miscarriage seem to vary widely. Before the placebo arm of the trial was discontinued in 2011, 42.5 percent of women who got pregnant while on Truvada experienced pregnancy loss, compared to 32.3 percent of women who got pregnant while receiving placebo, and 27.7 percent of women who got pregnant while on tenofovir. After 2011, 37.5 percent of women who got pregnant while on Truvada and 36.7 percent of women who got pregnant while taking tenofovir experienced pregnant loss. But Heffron said the limited number of pregnant women in the trial makes the variations in pregnancy loss statistically insignificant.
“You’d need more pregnancies to show something statistically, when there’s a very small difference,” like that found in her study, she said.
Previous studies have also found that, in babies born to mothers on Truvada, the baby’s bone mineral density was slightly lower, though it’s unclear what that means, and that the head circumference of the infants was slightly smaller—but only slightly. “It was a fraction of a centimeter,” said Heffron.
Research to Build On
These results from the Partners PrEP study were met with excitement by others studying PrEP in women. Erika Aaron, a nurse practitioner who specializes in women and HIV, and assistant professor at Drexel University College of Medicine in Philadelphia, called the Partners PrEP study a step in the right direction.
“It’s encouraging that there were no significant differences between HIV-negative women on medicines for PrEP and women on placebo. We need more numbers and to see this consistently through other studies, but it opens the possibility that providers will feel more comfortable using this intervention in the periconception and prenatal period,” she noted.
The Partners Demonstration Project, a follow up to the Partners PrEP study, is currently following 15 HIV-negative pregnant women and their HIV-positive partners. They will track PrEP use, adherence, pregnancy outcomes, and follow the infant’s development during the first year of life.
In addition, Aaron is one of three principle investigators for the PrEPception study, currently underway in Philadelphia, Boston and Baltimore. Like the Partners Demonstration Project, the PrEPception study will follow women who are interested in conceiving a child with their HIV-positive partners. It will track whether they adhere to the PrEP regimen, correlate PrEP drug levels with adherence self-reports, record barriers to adherence, and monitor pregnancy outcomes.
“It will be the first such study on U.S. women,” said Aaron.
Giving Women Smart Choices
The CDC PrEP guidelines released in May encourage health care providers to include PrEP in part of a larger conception discussion with women in relationships with HIV-positive men. Other options can include reproductive technology, such as sperm washing with intrauterine insemination or in vitro fertilization. The American College of Obstetricians and Gynecologists also provide guidelines that encourage ob-gyns to counsel their patients on PrEP and other HIV prevention strategies.
PrEP won’t be the right answer for every woman, of course. When she heard about these findings from the Partners PrEP study, Watson, now 25, said that it wouldn’t change her mind about using PrEP if she were to get pregnant again.
“I’m not good at taking pills and I’m not concerned about transmission with the risk next to zero,” said Watson, who, along with her daughter Valerie, remains HIV negative. “That is exciting news for others, though.”
Watson’s assertion that her risk is already “next to zero” is in line with a mathematical modeling study demonstrating that if the HIV-positive partner is on treatment, his viral load is suppressed, and the couple confines condomless sex to the woman’s fertile period, PrEP may offer no additional benefits.
That’s a big “if,” though. And some suggest that it takes the power out of women’s hands. PrEP gives women control over their risk for the first time.
“That’s why this is an issue of reproductive justice,” Aaron said. “PrEP allows a woman to control her own destiny by not having to rely on her partner’s behavior, his ability to take ART, to have an undetectable viral load, to get tested. These benefits far outweigh the risks [of PrEP].”
Heather Boerner is a San Francisco-based journalist and author of “Positively Negative: Love, Pregnancy, and Science’s Surprising Victory Over HIV.”