Estimating six-cycle efficacy of the Dot app for pregnancy prevention.
To assess six-cycle perfect and typical use efficacy of Dynamic Optimal Timing (Dot), an algorithm-based fertility app that identifies the fertile window of the menstrual cycle using a woman's period start date and provides guidance on when to avoid unprotected sex to prevent pregnancy. We are conducting a prospective efficacy study following a cohort of women using Dot for up to 13 cycles. Study enrollment and data collection are being conducted digitally within the app and include a daily coital diary, prospective pregnancy intentions and sociodemographic information. We used data from the first six cycles to calculate life-table failure rates. We enrolled 718 women age 18-39 years. Of the 629 women 18-35 years old, 15 women became pregnant during the first six cycles for a typical use failure rate of 3.5% [95% CI 1.7-5.2]. All pregnancies occurred with incorrect use, so we did not calculate a perfect use failure rate. These findings are promising and suggest that the 13-cycle results will demonstrate high efficacy of Dot. While final 13-cycle efficacy results are forthcoming, 6-cycle results suggest that Dot's guidance provides women with useful information for preventing pregnancy.