NEW YORK (Reuters Health) – Use of tenofovir in HIV-infected women during pregnancy is not associated with small-for-gestational age (SGA) or low birth weight (LBW) in their offspring, researchers report in a February 29th online paper in AIDS.

“Overall,” Dr. George K. Siberry told Reuters Health by email, “the findings of this study should reassure clinicians and the pregnant women under their care that taking tenofovir during pregnancy does not appear to cause growth problems for the fetus and infant.”

Dr. Siberry, with the National Institutes of Health in Bethesda, Maryland and colleagues note that although the agent is proven to be safe and effective in HIV-infected adults, its use for treatment of maternal HIV infections and for prevention of maternal-infant HIV transmission has been limited by concerns about possible detrimental effects.

To investigate further, the team examined data on 2029 uninfected children with maternal antiretroviral information taking part in a cohort study. The proportion of mothers taking tenofovir in pregnancy rose from 14% in 2003 to 43% in 2010. In all, the agent was used by 449 (21%).

The investigators found there was no difference between newborns exposed to combination regimens with or without tenofovir in terms of SGA (adjusted odds ratio 0.96; p=0.85), LBW (aOR 0.73; p=0.14), length-for-age z-scores (LAZ) (aOR 1.18; p=0.58), and head circumference-for-age z-scores (HCAZ) (aOR 0.82; p=0.39).

However at 1 year, infants exposed to tenofovir-containing regimens compared to those who were not had significantly lower adjusted mean LAZ (-0.17 vs -0.03; p=0.04) and HCAZ (0.17 vs 0.42; p=0.02), according to the report.

“We are not sure how to explain the slightly smaller body length and head size at age one year in infants whose mothers took tenofovir during pregnancy, and we are not sure if these small differences have any significance,” Dr. Siberry commented.

“We do not think that these findings at one year should be a reason to avoid tenofovir during pregnancy,” he concluded, “but it will be useful and important to see if similar observations are made in other large studies.”

Safety of tenofovir use during pregnancy: early growth outcomes in HIV-exposed uninfected infants

AIDS 2012.