Risk of Adverse Birth Outcomes in Women With HIV Using Tenofovir-Emtricitabine

The risks for adverse birth outcomes in pregnant women with HIV were not higher in women receiving tenofovir, emtricitabine, and ritonavir-boosted lopinavir (TDF–FTC–LPV/r) antiretroviral therapy (ART) compared with women receiving zidovudine, lamivudine, and ritonavir boosted lopinavir (ZDV–3TC–LPV/r) or tenovir, emtricitabine, and ritonavir-boosted atazanavir (TDF–FTC–ATV/r), according to findings published in the New England Journal of Medicine.

The risks of preterm birth (<37 completed weeks of gestation), very preterm birth (<34 completed weeks), low birth weight (<2500 g), and very low birth weight (<1500 g) were assessed using data from 2 US-based birth cohort studies encompassing 4646 birth outcomes.

The number of infants or fetuses exposed to TDF–FTC–LPV/r during gestation was 2.8% and lower than both TDF–FTC–ATV/r and ZDV–3TC–LPV/r, which were 11.6% and 20.5%, respectively. The risks for preterm birth (risk ratio [RR] 0.90; 95% CI, 0.60 to 1.33) and low birth weight (RR 1.13; 95% CI, 0.78 to 1.64) were similar in women receiving ZDV–3TC–LPV/r compared with women receiving TDF–FTC–LPV/r. Women receiving TDF–FTC–ATV/r had a similar or slightly higher risk for preterm birth (RR 1.14; 95% CI, 0.75 to 1.72) and low birth weight (RR 1.45; 95% CI, 0.96 to 2.17) compared with the women receiving TDF–FTC–LPV/r. No significant differences in the risk for very preterm birth or very low birth weight were observed between any of the treatment regimes.

Investigators noted a lack of power in predicting the risk for very preterm birth and very low birth weight in the TDF–FTC–LPV/r group due to the low number of women receiving this treatment and the rarity of these outcomes. This may have influenced the lack of significant differences in these outcomes for this particular group, which is contrary to some other reports in the literature. Concerns regarding this treatment regime remain as it is also not among the first-line treatment options currently recommended by the World Health Organization. Further limitations of this study were the lack of information on other important preterm birth predictors — which could confound analysis depending on their distributions among the treatment groups — and an overall lack of generalizability to populations outside of the United States.

Investigators concluded that higher risks of adverse birth outcomes in infants exposed to TDF–FTC–LPV/r were not observed compared with the other two regimes, although this regime was not used as frequently as the other two regimes. The results also suggested that using TDF–FTC–ATV/r during pregnancy carries similar or lower risk of preterm birth and low birth weight as the use of ZDV–3TC–LPV/r.

Reference

Rough K, Seage GR, Williams P, et al. Birth outcomes for pregnant women with HIV using tenofovir–emtricitabine. New Engl J Med. 2018; 378:1593-1603.