Effectiveness of levonorgestrel implant and depot medroxyprogesterone acetate injectable for women living with HIV on efavirenz: a prospective cohort study.

Abstract

Objective: We compared the contraceptive effectiveness of typical-use LNG implant and depot medroxyprogesterone acetate (DMPA) injectable during efavirenz use.

Design: We conducted a prospective cohort study of women living with HIV (WLHIV) on efavirenz-containing antiretroviral treatment in Lilongwe, Malawi. Eligible participants were 18-40 years of age and initiating LNG implant or DMPA injectable with desire to prevent pregnancy for 4+ years. Study visits and urine pregnancy testing occurred at enrollment, week 4, and every 24 weeks up to week 192. Malawi's efavirenz-to-dolutegravir transition shortened our duration of efavirenz follow-up.

Methods: Pregnancy incidence rates/100 person-years (PY) and an incidence rate difference (IRD) were estimated using an inverse-probability-weighted Poisson model.

Results: We enrolled 1,179 WLHIV on efavirenz: 592 and 587 chose to initiate the LNG implant and DMPA, respectively. Median follow-up during efavirenz use was 1.1 years (IQR: 0.5-1.7). Estimated pregnancy incidence rates were 6.6/100 PY (95%CI: 5.0, 8.7) in the LNG implant enrollment group (50 pregnancies) and 7.3/100 PY (95%CI: 5.5, 9.7) in the DMPA enrollment group (54 pregnancies), IRD -0.7/100 PY (95%CI: -3.5, 2.0). Results were similar in an analysis of first incident pregnancy during continued typical use of LNG implant (5.7/100 PY) versus continued typical use of DMPA (5.7/100 PY), IRD 0.0/100 PY (95%CI: -2.6, 2.7).

Conclusions: In many settings, LNG implant has better contraceptive effectiveness than DMPA injectable. However, for WLHIV on efavirenz, we observed similar typical-use effectiveness for LNG implant versus provider-administrated DMPA injectable during the initial 1-2 years of use.