Estimating six-cycle efficacy of the Dot app for pregnancy prevention

Abstract

To assess six-cycle perfect and typical use efficacy of Dynamic Optimal Timing (Dot), an algorithmbased 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. Study design: 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. Results: 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. Conclusions: These findings are promising and suggest that the 13-cycle results will demonstrate high efficacy of Dot. Implications: While final 13-cycle efficacy results are forthcoming, 6-cycle results suggest that Dot's guidance provides women with useful information for preventing pregnancy.

Perfect- and typical-use effectiveness of the Dot fertility app over 13 cycles: results from a prospective contraceptive effectiveness trial

“…To estimate the perfect-and typical-use effectiveness of the Dot app for pregnancy prevention, we adapted guidelines for contraceptive effectiveness studies [8], including FABMs [9], to the context of a fertility app [7]. The study design reflects relevant points included in a recent systematic review of FABM effectiveness studies [10].…”

“…Study participants were recruited between 7 February 2017 and 10 August 2017 from a pool of new Dot users who lived in the continental United States. Prior to enrolment, participants had downloaded the app on their Android phones, chosen to prevent pregnancy, entered their second menstrual period start date, met initial recruitment criteria and replied affirmatively to a pop-up message describing the study and asking if they were interested in participating [7,11,12].…”

“…Due to multiple steps required in the original enrolment process [12], enrolment was low during the early months of recruitment. With a streamlined process, enrolment increased to 718 (40.8% of those interested and preeligible) participants [7,12].…”

“…Proofmode and Amplitude collected data including, but not limited to, how many times the app was opened, entry of a menstrual period start date and sexual history data. Both Proofmode and Amplitude are described in more detail elsewhere [7,12].…”

“…An interim analysis of Dot's effectiveness [7] found that early typical-use failure rates were low and that women used Dot successfully to prevent pregnancy [7]. The current paper analyses the full 1 year (13 cycles) perfect-and typical-use effectiveness from an observational, prospective effectiveness study of Dot, conducted from February 2017 to October 2018.…”