A Prospective Observational Study on the Contraceptive Effectiveness of the Natural Cycles Application (The VENUS Study)
The goal of this observational study is to measure the effectiveness of the Natural Cycles digital birth control application at preventing pregnancy in sexually active women aged 18 to 35 with no known history of infertility. The main questions it aims to answer are: * What is the pregnancy rate of the application over one year, for all users? * What is the pregnancy rate of the application over one year, for users who follow the application's instructions perfectly? Participants will: * Use the Natural Cycles application for birth control for up to one year. * Log information about daily sexual activity in the app. * Complete a questionnaire at the beginning and end of their participation. * Perform urine pregnancy tests (provided by mail) upon entry to the study, at the start of every cycle during the study, and upon exit from the study.
• Wants to avoid pregnancy for 13 cycles.
• Is willing to rely solely on Natural Cycles as their sole contraception method for 13 cycles.
• Is not currently using permanent contraceptive methods, such as sterilization (of either the user or their partner), or hormonal methods, such as the hormonal contraceptive implant or IUD.
• Has an intact uterus, both ovaries and both fallopian tubes to the best of their knowledge.
• Has an average cycle length between 21 and 35 days. The user anticipates heterosexual intercourse at least once a month in the next year.
• Is willing to enter data on a daily basis and perform pregnancy tests as requested by protocol.
• Is willing to complete a satisfaction survey at the end of her study participation.