HIV Risk Quadruples for Postpartum Women

Heather Boerner

March 05, 2018

BOSTON — During pregnancy and in the first 6 months after childbirth, women are three to four times more likely than their nonpregnant counterparts to acquire HIV, and the risk does not seem to be related to a lack of condom use, a new analysis suggests.

This is a call to action for clinicians, said Renee Heffron, PhD, from the University of Washington in Seattle, who presented the data here at the Conference on Retroviruses and Opportunistic Infections 2018.

"We have tremendous opportunities in antenatal and postnatal care to promote HIV prevention and care," she explained. For example, testing of women can be increased during pregnancy, especially if a woman has a partner living with HIV or lives in an area with a high prevalence of HIV.

The effort to keep women from contracting the virus during and after pregnancy can make it easier to screen male partners and initiate treatment when necessary, said Heffron. And it can provide an opening for clinicians to talk to women about ways to protect themselves, including pre-exposure prophylaxis (PrEP).

Slow and Steady Increase in Risk

Researchers have been looking at this issue for years, with mixed results. So Heffron and her team combed through data from two prospective studies to identify serodiscordant couples in eastern and southern Africa who had been followed for at least 48 months.

All the women had partners with detectable viral loads. Women with male partners being treated with suppressive antiretroviral therapy were excluded from the analysis, because consistent antiretroviral therapy has been shown to prevent the transmission of HIV.

In the final cohort of 2517 HIV-negative women, there were 686 pregnancies and 78 instances of HIV.

Pregnancy tests were performed monthly, or as needed, so the researchers could sort the women who acquired HIV by trimester.

They found a slow and steady increase in HIV risk as pregnancies progressed that continued until 6 months after childbirth.

Table. HIV Acquisition

Time Period Rate per 1000 Sex Acts
First trimester 2.19
Second and third trimesters combined 2.97
Postpartum period 4.18


In contrast, for women who were not pregnant or in the postpartum period, HIV risk was 1.05 for every 1000 sex acts.

"The data are pretty striking when you look at them," said Heffron. "We didn't really expect to see that, especially in the postpartum period."

Even after factors like condom or PrEP use, a woman's age, and the viral load of her partner were controlled for, the adjusted risk ratio of HIV acquisition during the later stage of pregnancy was 2.82. In the 6-month postpartum period, it was 3.97.

"Our findings suggest that biologic changes during pregnancy and postpartum may increase HIV risk," said Heffron. Although her team is not studying what those mechanisms are, it is possible that changes in hormones and immune function play a role, she added.

"This shows us that our screening of women in pregnancy has been far too loose," said James McIntyre, MBchB, from the Anova Health Institute in Johannesburg, who has studied the prevention of HIV transmission from mother to child for years. "We need repeated testing during pregnancy. And we shouldn't be assuming that just because a woman is negative at the beginning of her pregnancy, she will stay that way."

Our findings suggest that biologic changes during pregnancy and postpartum may increase HIV risk.

The findings are "remarkable," he added, The assumption has always been that these women were not using condoms during sex, but these data point in another direction. If the risk is biologic, then the strategy should focus on biomedical prevention, he explained.

"We ought to really consider talking to women about PrEP during pregnancy," said McIntyre. "It's increasingly important because women are at incredibly high risk of infection."

In fact, the findings support guidelines from the World Health Organization and the Centers for Disease Control and Prevention, which list PrEP as an option during pregnancy and breast-feeding, Heffron pointed out.

But given these data, perhaps this should be changed, said Wafaa El-Sadr, MD, from the International Center for AIDS Care and Treatment Programs at Columbia University in New York City.

"Now that we know the risk in this population," maybe the recommendation should say, "should be used," said El-Sadr.

Heffron and El-Sadr have disclosed no relevant financial relationships. McIntyre reports serving as a consultant for Novavax.

Conference on Retroviruses and Opportunistic Infections (CROI) 2018: Abstract OA45. Presented March 5, 2018

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