BOSTON -- Babies of HIV-positive mothers taking an antiretroviral drug recommended for pregnant women have reduced bone density, a researcher said here.
In a cohort study, babies of mothers taking tenofovir (Viread) had an average whole-body bone mineral content about 8 grams less than babies whose mothers did not use the drug, according to George Siberry, MD, of the National Institute of Child Health and Human Development in Bethesda, Md.
But while the difference is statistically significant, it's not clear if it will persist or what the clinical impact would be if it does, Siberry told reporters at the annual Conference on Retroviruses and Opportunistic Infections.
Indeed, the finding is a "signal" whose meaning is up in the air, commented Elaine Abrams, MD, of Columbia University in New York City, who moderated a press conference at which some details of the study were reported.
"It says the babies of moms who took the drugs are different," Abrams told MedPage Today. "What that means in terms of a child's growth and bone development ... we have no idea."
While tenofovir has long been known to have an impact on bone mineral density in children and adults taking it for HIV infection, it's recommended for pregnant women because of its good efficacy and record in preventing mother-to-child transmission, Siberry said.
"The concern ... has always been there, but there hasn't been any evidence to say one way or the other if that concern held up," he told MedPage Today.
He added it's too early to think about changing recommendations, but further studies to see if the bone issues persist and have a clinical impact are planned.
The studies "should really give us a much better handle on what to do next," Siberry said.
At the moment, Abrams said, "I wouldn't know what to tell a woman about the findings."
The results come from a substudy involving HIV-positive and pregnant participants in the Pediatric HIV/AIDS Cohort Study in nine states and Puerto Rico, Siberry reported.
The primary endpoint was whole-body bone mineral content of the infant assessed by hologic dual-energy x-ray absorptiometry (DXA) scanning.
All told, 143 DXA scans could be evaluated, 74 among babies born to mothers in the tenofovir arm and 69 among those born to women who were not taking the drug.
Infants born to mothers in the tenofovir arm had, on average, a whole-body bone mineral content of 56 grams, compared with 63.8 grams for infants born to mothers who used other anti-HIV drugs.
The 7.8-gram difference -- 12.2% on average -- was significant at P=0.002. The difference was slightly attenuated in an analysis adjusted for such things as gestational age, body length, and race/ethnicity, but remained significant at P=0.004, Siberry reported.
He cautioned that the study was not randomized so that residual confounding is possible. He also noted that the study is a cross-sectional snapshot, so the difference might not persist.