Tenofovir exposure in utero and linear growth in HIV-exposed, uninfected infants

Tenofovir (TDF) affects bone health and is widely used in pregnancy but data are limited on the effects of TDF exposure in utero. We examined the association between duration of in-utero TDF exposure and linear growth in HIV-exposed, uninfected (HEU) infants.

A prospective cohort of pregnant women initiating TDF-containing regimens at primary care services in Cape Town, South Africa, were enrolled and followed with their breastfeeding infants through 12 months postpartum.

Length-for-age z scores (LAZ) were calculated from infant lengths reported at birth and measured at 6, 12, 24, 36 and 48 weeks, using Fenton and WHO standards. Linear mixed-effects models were used to examine the association between duration of TDF exposure and LAZ over time.

In 464 singleton mother-infant pairs (median CD4 at ART initiation, 346 cells/μl; viral load (VL), 4.0 log10 copies/ml), the median duration of in-utero TDF exposure was 16.7 weeks (interquartile range, IQR 11.0-22.0) with 31, 44 and 25% of infants exposed to less than 12, 12-22 and more than 22 weeks of TDF, respectively. Overall, 12% of children were stunted (LAZ < -2) at 48 weeks. Duration of exposure was not associated with LAZ: adjusted mean difference for more than 22 vs less than 12 weeks, -0.12 (95% CI -0.47 to 0.23); 12-22 vs less than 12 weeks, -0.06 (95% CI -0.35 to 0.24). Mean LAZ was 0.15 lower per log increase in maternal VL at ART initiation (95% CI -0.29 to -0.0001).

These data suggest no association between duration of TDF exposure in utero and early linear growth.