The average bone mineral content (BMC) of infants of mothers who took tenofovir during pregnancy was 12.2% lower than was the average BMC of infants who were not exposed to the drug in utero, according to a controlled study.
The study’s participants were infants of mothers with HIV infections. The mothers enrolled in the study from April 2011 to June 2013, at 14 U.S. clinical sites. Late in pregnancy, 74 of the infants’ mothers had taken tenofovir disoproxil fumarate (TDF), which when combined with other antiretroviral drugs, is the preferred initial therapy for adults with (HIV) infection. The study’s additional participants were 69 infants of mothers who had not taken tenofovir during gestation. Infants from both groups had their BMC measured within a month of their births. All of the infants were born no earlier than after a 36-week pregnancy, did not have HIV infection, and were singletons.
Dr. George K. Siberry
The average whole-body BMC (with head) of infants exposed to TDF in utero was 56.0 g, compared with 63.8 g for unexposed infants (P = .002). For whole-body less head BMC, the mean was 33.3 g in the TDF-exposed group, compared with 36.3 g in the unexposed group (P = .038), showing that for TDF-exposed infants, the average whole-body less head BMC was 8.3% smaller than was that of the unexposed infants.
According to the researchers’ adjusted linear regression model, for TDF-exposed infants, the mean whole-body BMC (with head) was 5.3 g lower (P = .013) in the TDF-exposed infants. For the mean whole-body less head BMC, the adjusted model showed that this measurement was 1.9 g lower in the TDF-exposed infants (P = .15).
“The present study provides strong evidence of a biologic effect of maternal TDF on infant bone. However, the lack of infant BMC reference standards makes it difficult to determine if the lower BMC in tenofovir-exposed infants is abnormal,” according to Dr. George K. Siberry and his colleagues.
Read the full study in Clinical Infectious Diseases (doi: 10.1093/cid/civ437).