October 07, 2018
2 min read

Protease inhibitor use during first trimester associated with higher risk for preterm birth

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SAN FRANCISCO — During pregnancy, most women living with HIV who are on treatment achieve viral suppression, but many experience a viral load rebound after pregnancy, according to preliminary study findings presented at IDWeek. In addition, the study showed a higher risk for preterm birth associated with protease inhibitor use in the first trimester, researchers said.

“Our study had two aims. One was to descriptively look at trends in CD4 count, viral loads, antiretroviral regimens and pregnancy outcomes in women in the SMARTT group” — or the Surveillance Monitoring for ART Toxicities group — “which is a cohort within the Pediatric HIV/AIDS Cohort Study (PHACS),” Brigid O’Brien, DO, a pediatric infectious disease fellow at Tulane University School of Medicine, said during a presentation. “The second aim was to examine the association between protease inhibitors (PIs) with preterm birth in these women.”

As previously reported, 40% of people living with HIV, including men who have sex with men, and heterosexual men and women, have future parenting desires.

“With advancements in HIV therapy, women with HIV are choosing to have more than one pregnancy. We know that unintended pregnancies occur as well,” O’Brien said. “Previously, studies have shown that there is often a postpartum viral rebound seen in these women after pregnancy.”

For the PHACS SMARTT study, O’Brien and colleagues identified 699 women who had multiple pregnancies between 2007 and 2018. The researchers measured the mean log10 viral load early and late in pregnancy and compared them between both pregnancies. They observed a 0.42  decrease in the log10 VL between the early in pregnancy measurements and a 0.16 decrease in the log10 VL between the late in pregnancy measurements between the first and second pregnancies(P < .001 for each). However, there was a 0.61  (P < .001) increase in the log10 viral load between the end of the first pregnancy and early in the next pregnancy.

Most women (55%) remained on a PI during their first and second pregnancies. Women not on a PI for either pregnancy comprised 16% of the study cohort, whereas 14% of women were on a PI for their first pregnancy but not for their second and 15% were not on a PI for their first pregnancy but were for their second.

The preterm birth rate increased 4.3% between the first and second pregnancy among women who started and remained on a PI during both pregnancies. Women who were not on a PI for either pregnancy experienced a 2% decrease in preterm birth rates from their first to second pregnancy. Additionally, those who switched from PI to non-PI experienced a 4.7% decrease in preterm birth rates. O’Brien and colleagues observed stable preterm birth rates from the first to second pregnancy among women who switched from non-PI to a PI.

When the researchers evaluated all pregnancies in an adjusted model, PI use in the first trimester of pregnancy was associated with an increased rate of preterm births (adjusted OR = 1.35; 95% CI, 1.02-1.97).

“We saw that 80% of the women achieved viral suppression in the first pregnancy, and there was a rebound following the next pregnancy,” O’Brien said. “Preterm birth was associated with protease inhibitor use, specifically early in pregnancy. When we compared the two pregnancies, the rates of preterm birth were lower for women who remained on or changed to a non-protease inhibitor-containing regimen, and those that remained on a protease inhibitor-containing regimen had higher rates of preterm birth.” – Marley Ghizzone


O’Brien B, et al. Abstract 935. Presented at: IDWeek; Oct. 3-7, 2018; San Francisco.

Cohn SE, et al. Open Forum Infect Dis. 2018;doi:10.1093/ofid/ofy232.

Disclosures: O’Brien reports no relevant financial disclosures. Please see the abstract for all other authors’ relevant financial disclosures.