Tenofovir use and pregnancy among women initiating HAART.

OBJECTIVE

Recent studies have raised concerns about a change in rates of pregnancy among HIV-negative women exposed to tenofovir. Here, our objective was to determine among HIV-positive women whether use of tenofovir at HAART initiation or thereafter is associated with subsequent changes in incidence of pregnancy.

DESIGN

Analysis of prospectively collected clinical data.

METHODS

We used Cox proportional hazards models and logistic regression to estimate hazard ratios and odds ratios for the association of baseline tenofovir use and first incident pregnancy. We used marginal structural Cox models to estimate hazard ratios for the association of current tenofovir use and time to first incident pregnancy.

RESULTS

We studied 7275 women, of whom 1199 were initiated on tenofovir-based HAART regimens, and who experienced a total of 894 pregnancies in 17,200 person-years of follow-up. Analyses showed slight reductions in hazards of pregnancy among women who used tenofovir but without sufficient precision to draw strong conclusions. Sensitivity analyses confirmed main results.

CONCLUSIONS

Tenofovir may be associated with a lower hazard or rate of pregnancy in women receiving HAART. However, conclusions are limited by low precision, the observational nature of the data, and possible uncontrolled confounding by temporal trends in contraception use and other factors.