Preventive TB Treatment is Safer Postpartum than in Pregnancy in Women with HIV

In pregnant women living with HIV, treatment outcomes are better when preventive tuberculosis (TB) treatment is given after delivery when compared to receiving the therapy during pregnancy, according to a study published in The New England Journal of Medicine.

A National Institutes of Health-funded study aimed to determine the safety, efficacy, and appropriate timing of using isoniazid to prevent TB in 956 pregnant women with HIV. All but 1 of the women involved in the study were taking antiretroviral therapy at the start of the study. Oftentimes, pregnant women are excluded from clinical research, which can lead to an information gap. This can sometimes pose a danger to maternal and infant health, Anthony Fauci, MD, said in a press release.

The investigators randomly assigned these women to receive 300 mg isoniazid preventive therapy for 28 weeks, which was initiated either during pregnancy or 12 weeks after delivery. Then, the new mothers and their infants were followed through 48 weeks after delivery. The participants had a follow up appointment every 4 weeks and self-reported their adherence to the isoniazid regimen. The investigators monitored pill counts and determined that 88% of the study participants completed at least 90% of the treatment regimen.

“For a long time, the safety, efficacy and appropriate timing of giving isoniazid therapy to prevent tuberculosis in pregnant women — nobody really knew. They just did it. Sometimes you gave it to a woman during pregnancy; sometimes you gave it to her after the pregnancy,” Fauci, the Director of the National Institute of Allergy and Infectious Diseases, told Contagion®. “There was never any organized way to figure out A) what was the best and most effective and B) was there any deleterious effect in one versus the other? I think it’s important that we do know that right now.”

The study authors determined that isoniazid was similarly safe for use as TB prevention for both groups.

But, according to the authors, the troubling part of the findings was that the incidence of poor pregnancy outcomes in women who took isoniazid during pregnancy was greater than those who took it postpartum. They believe their findings warrant further investigation into alternative TB prevention methods for pregnant women.

There were more poor health outcomes for fetuses and newborns of the participants who began taking isoniazid during pregnancy than those who started taking the isoniazid postpartum (24% versus 17%, respectively), the investigators learned. They noted that the poor outcomes included stillbirth, spontaneous abortion, low birth weight, preterm delivery, and congenital abnormalities. However, there did not seem to be a significant difference between the 2 groups once the investigators evaluated these poor outcomes individually.

“I think this will change practice in the sense of people now will know that there’s a scientific basis for making a decision as opposed to guessing,” Fauci added. “Women are very reluctant to take any medication during their pregnancy. If you tell them, ‘Guess what? We have a study that shows all in all, it’s better and much safer to give you the medication after [delivery],’ I think they would welcome that. I don’t think we’d have trouble trying to convince them.”