Birth control that works with your body

A clinical study is a research study that helps determine the safety and effectiveness of new medical treatments, devices, or technologies.

According to the FDA, Digital Contraception can be *93% effective for typical use at preventing pregnancy, compared with the pill at 93% and male condoms at 87%. This study will evaluate the effectiveness of Flo’s particular Digital Contraception, which uses Apple Watch temperature data and menstrual cycle tracking to predict pregnancy risk.

*Reference “Contraception and Birth Control Methods.” Centers for Disease Control and Prevention. 5 Aug, 2024. “Birth Control” FDA Office of Women’s Health, 10 May, 2024

Flo Health is a leading women's health technology company and creator of the Flo app, used by over 380 million women worldwide for period and cycle tracking. Flo Digital Contraception turns your period tracker into a digital form of birth control.

Lindus is a research organization that manages clinical trials. Flo is partnering with Lindus Health to conduct this study safely and effectively. That includes managing enrollment, electronic consent, monthly surveys, participant support, and communications.

The study lasts 13-18 months and you can drop out at any time. It begins after you’ve completed enrollment and then logged one period.

No. This is a virtual study. Participate entirely from home using your own Apple Watch (Series 8, Series 9, Series 10, or Ultra) and the Flo app. No clinic visits required.

Temperature-based birth control tracks changes in your body temperature to identify when you're at risk of getting pregnant. After ovulation, your temperature rises slightly, signaling lower pregnancy risk. This study evaluates the effectiveness of combining temperature tracking from your Apple Watch with period logging in the Flo app to provide a hormone-free birth control option. This gives women another way to prevent pregnancy that works with their body, not against it.

On low pregnancy risk days, the Flo app shows you're less likely to get pregnant. On high pregnancy risk days, the app alerts you to use barrier methods (like condoms) or abstain from sex to prevent pregnancy. You'll check your daily pregnancy risk in the investigational app and make informed decisions about sex based on what you see. Note that Flo Digital Contraception does not protect against STIs.

Yes. You can opt out of the study at any time via the Flo app or by informing Lindus Health in one of the clinical study surveys.

Our study aims to confirm the effectiveness of Flo’s digital contraception method before offering it as an option to our community.

The FDA regulates digital contraceptives as medical devices.

We need to collect robust, real-world data to prove that Flo’s digital contraceptive technology is a safe and effective form of contraception for women of all ages and backgrounds.

This evidence is necessary to support our FDA clearance application for Flo as a medical device.

For the study to work accurately and give you the most precise predictions, you must:

• Log your period every cycle. This is the most important date to log.
• Wear your Apple Watch every night. This is how we track your body temperature.
• Log partnered sex every time. Plus, include if it was protected or not.
• Check your predictions daily. Use protection when your fertility is high.

You can also log luteinizing hormone (LH) ovulation tests. This is optional but can help improve your predictions.

Our predictions are based on your logged temperature and cycle data. The more consistently you log, the more accurate your predictions will be. In this clinical study, we are evaluating how well our digital contraceptive performs.

For the best results when tracking your temperature, remember to wear your Apple Watch (Series 8 or later) overnight and keep it charged. Your Apple Watch will measure your body temperature throughout the night and automatically sync to your Flo account in the morning.

During each menstrual cycle, there’s a window of time when your fertility is higher, and the risk of getting pregnant from unprotected sex increases. This usually happens in the days around ovulation.

Flo’s digital contraceptive aims to help you prevent pregnancy by predicting when your risk of getting pregnant is high. By estimating the timing of ovulation based on the data you log, it highlights the days when you should use protection (or avoid sex). On days outside this time period, the risk of getting pregnant is very low.

An “investigational” device is one that is currently being tested to see how well it works, before it’s officially approved by the FDA. Because this version of Flo’s digital contraception is still in the testing phase, it hasn’t been approved by the FDA. However, they have reviewed our study plan and pre-clinical testing, and have given us permission to conduct this study in the US.

To participate, you must:

• Be 18 or older
• Live in the United States
• Want to prevent pregnancy
• Have at least nine menstrual cycles in a calendar year

You should not participate if you’re:

• Trying to conceive
• Pregnant
• Breastfeeding
• Recently postpartum/after pregnancy
• Not currently fertile
• Under 18 years old
• Living outside of the United States

Reasons why you might not be currently fertile include having had three or fewer menstrual cycles since being pregnant, known fertility issues, or currently using hormonal, implant, or procedure-based birth control, for example an intrauterine device (IUD).

You will need:

• The Flo app on your phone
• An Apple Watch Series 8 or later

You need to have an Apple Watch Series 8 or later to collect wrist temperature data — the series number is on the back of your watch.

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You should use male condoms on days that are labelled ‘Use protection’. If you decide to start using hormonal birth control, you’ll need to let us know and leave the clinical study. This includes the pill, vaginal contraceptive ring, patch, implant, hormonal IUD, and contraceptive injection.

You’ll also need to leave the study if you choose to use a copper IUD. Any contraception reminders you have in the Flo app will automatically stop when you join the study. Using the emergency contraceptive pill will impact your predictions, so it’s important to log this and use barrier contraception (such as a male condom) each time you have sex until the start of your next period.

You can join the study. However, when you quit hormonal contraception, your cycle can take about 3 months to stabilize. Our algorithm will take this into account to provide you with the safest predictions during this transition period. This means you may see more “Use Protection” days during your first few weeks.

The risks of participating in the study are:

Pregnancy: The primary risk with any contraception is an unintended pregnancy. We’ve designed this study to evaluate the effectiveness of Flo’s digital contraceptive tool in a real-world setting. We will guide you on correct usage to minimize this risk.

Inaccurate predictions: Flo’s digital contraception predictions are produced based on the information you provide. Please ensure that the data you provide is true, accurate, and complete. Inaccurate, false, or incomplete data can lead to predictions that are not suitable for you. Using Flo’s digital contraception while on hormonal birth control can also lead to inaccurate predictions.

If you have irregular cycles: Irregular cycles result in less predictable ovulation timing, which may increase the risk of unintended pregnancy when using fertility awareness methods. If the data you share shows that you might have an irregular cycle, you’ll see more days when you should avoid unprotected sex.

Sexually transmitted infection (STI) exposure: Flo’s digital contraception does not protect against STIs. Use a male condom to protect against STIs.

During the study, Flo will use participant data to help us assess how effective Flo’s digital contraceptive is and provide evidence to the Food and Drug Administration (FDA) for regulatory approval.

For the purpose of running this study, Flo has partnered with Lindus Health, a research organization that helps us investigate how effective our technology is. For this purpose only, we will share just your study data with Lindus Health.

As always, Flo is committed to protecting your data, which we never sell for any reason. For more information on our privacy and security practices, please read our Privacy Policy and Security Policy.

When you participate, you will get Flo Premium, free, for 2 years. This will begin on the day you successfully join the clinical study.

If you already have a Premium subscription that automatically renews with Apple, you will need to cancel it.

You can manage or cancel your subscription anytime in your Apple app store settings.