Background: Sub-Saharan Africa is disproportionately affected by high rates of unintended pregnancy. Contraceptive method failure is an important contributor to unintended pregnancy. Few data are available that compare pregnancy rates among different long acting contraceptive methods.
Methods: We analyzed data from the ECHO Trial, which assessed HIV incidence among 7829 women from 12 sites in Kenya, the Kingdom of Eswatini, South Africa, and Zambia who were seeking effective contraception and consented to be randomized to DMPA-IM, LNG implant, or copper IUD. Cox proportional hazards regression adjusted for condom use during last vaginal sex was used to compare pregnancy incidence during both perfect use (from initiation of method until first discontinuation for any reason) and typical use (from initiation of method until decline or change to a different contraceptive method). Cumulative pregnancy probabilities at 12-months were estimated using Kaplan-Meier methods.
Results: 7710 women contributed to this analysis. 70 pregnancies occurred during perfect use and 85 during typical use. Perfect use pregnancy incidence rates were 0.61 per 100 woman-years (wy) for DMPA-IM (95% CI 0.36-0.96), 1.06 for copper IUD (95% CI 0.72-1.50), and 0.63 for LNG implants (95% CI 0.39-0.96), with 12-month cumulative probabilities of 0.62% (95% CI 0.37-1.03), 1.09% (95% CI 0.73-1.64), and 0.64% (95% CI 0.39-1.04), respectively. Typical use incidence rates were 0.87 per 100wy for DMPA-IM (95% CI 0.58-1.25), 1.11 for copper IUD (95% CI 0.77-1.54), and 0.63 for LNG implants (95% CI 0.39-0.96) with 12-month cumulative probabilities of 0.90% (95% CI 0.59-1.36), 1.05% (95% CI 0.71-1.57), and 0.64% (95% CI 0.39-1.04), respectively. Typical use of copper IUD was associated with statistically significant higher risk of pregnancy compared to LNG implants (aHR 1.74; 95% CI 1.01-2.99).
Conclusions: In a randomized contraceptive trial of African women, both perfect and typical use of all contraceptive methods resulted in low pregnancy rates. Although we found that women using copper IUD had somewhat higher pregnancy rates than those using LNG implants, our findings provide strong justification to improve access to a range of contraceptive options including LNG implants and copper IUD for African women.