Flo Digital Contraceptive Study

The goal of this clinical trial is to learn if the Flo Digital Contraceptive (FDC) app can effectively prevent unintended pregnancy in women aged 18 years and older residing in the United States. The main questions it aims to answer are: What is the rate of unintended pregnancy in women aged 18-35 years using FDC as their sole method of contraception under typical-use conditions, measured using the Pearl Index? What is the cumulative probability of unintended pregnancy over 13 menstrual cycles for all participants, including those with regular and irregular cycles? Participants will: Use the Flo Digital Contraceptive app in 'prevent pregnancy' mode as their primary method of contraception for up to 13 menstrual cycles or 18 months, whichever comes first Wear an Apple Watch (Series 8 or later, or Ultra) while sleeping to collect nightly wrist temperature data, which the app uses to detect ovulation Log menstrual cycles, sexual activity, and any use of emergency contraception directly in the Flo app Complete monthly electronic surveys (ePROs) administered by the study team covering pregnancy status, adherence, safety, and experience Complete a baseline demographic survey at enrollment and an exit survey at the end of participation