BACKGROUND: Previous studies found that tenofovir-based ART use during pregnancy among women living with HIV is associated with lower bone mineral density (BMD) in neonates. It is unknown whether these differences persist beyond the neonatal period or exist among neonates born to women without HIV who used tenofovir-based PrEP during pregnancy.
METHODS: We utilized data from an ongoing evaluation of perinatal PrEP use in Kenya. In the parent study (NCT03070600), HIV-negative women were enrolled and offered tenofovir-based PrEP during pregnancy at 20 public clinics and followed through 9 months postpartum regardless of PrEP status. An extension cohort to evaluate safety outcomes enrolled mother-child pairs at 4 sites to be followed until the child’s 5th birthday. A subset of singleton children aged 36 months with in-utero PrEP exposure was randomly selected and matched to children without in-utero PrEP exposure on maternal age, education level, and child sex and age. Whole-body BMD was measured by dual-energy x-ray absorptiometry (DEXA) at Aga Khan University Hospital in Nairobi, Kenya. Linear regression adjusting for matching characteristics was performed to evaluate the relationship between BMD and PrEP exposure.
RESULTS: From December 2021 to December 2022, 40 children with in-utero PrEP exposure and 71 without PrEP exposure had whole-body BMD measurements. The median age at DEXA scanning was 36.7 months (IQR: 36.2-38.0), 40% of children were female, and the median maternal age at delivery was 27.6 years (IQR: 22.1-32.6). The median height for children at DEXA scanning was similar between those with and without PrEP exposure (94.3 cm vs. 94.0 cm, p=0.455). The median whole-body BMD for children with and without in-utero PrEP exposure was 418.5 mg/cm2 (IQR 399.2-440.0) and 423.0 mg/cm2 (IQR 395.5.0-457.5.0), respectively. There was no difference between mean whole-body BMD among children with and without in-utero PrEP exposure (adjusted mean difference -21.6 mg/cm2, 95% CI -60.1-17.0, p=0.270).
CONCLUSIONS: PrEP exposure was not associated with BMD or height at 36 months among children with mothers who used PrEP during pregnancy. Our findings suggest that in-utero PrEP exposure may not impact BMD into early childhood.