Illustrations by Marta Pucci

Reading time: 6 min

What is the difference between Clue Period Tracking mode and Clue Birth Control mode?

The science behind Clue Period Tracking mode and Clue Birth Control mode, and why they are different

Clue Birth Control is a new mode within the Clue app. It’s a  digital contraceptive designed to prevent pregnancy. How does it work? When you start using Clue Birth Control, you complete an eligibility checklist and then you enter your period start date. Clue Birth Control then tells you which days are high risk and low risk for pregnancy. 

You will start out with 16 days that are high risk for pregnancy each cycle. As you continue to track your period start dates, your predictions become more personalized and can have fewer high risk days. For Clue Birth Control to be effective at preventing pregnancy, you need to use a barrier method such as a condom on high risk days when you have sex that could result in pregnancy. 

How is the Clue Birth Control mode different from the Clue Period Tracking mode? Clue Period Tracking mode has many features, some of which track your menstrual cycle and well-being, but it wasn’t designed as a contraceptive. Clue Birth Control uses a different algorithm to predict your risk for pregnancy, and it’s been cleared by the FDA as a contraceptive device. 

Let’s dig deeper into what makes Clue Birth Control different from Clue Period Tracking mode.

Prevent pregnancy by tracking your cycle with Clue Birth Control

  • Download the Clue app on the App Store
  • Download the Clue app on the Play Store
an image of 3 mobile screens of the Clue app

The story behind Clue

Clue is used by over 12 million people across more than 190 countries. The app was originally created to help people learn about their bodies and gain insights into their menstrual and reproductive health. Talking about menstruation has historically been taboo, yet sexual and reproductive health, including menstrual health, is critical to a person’s overall well-being (1). Clue was designed to combine science and technology to address menstrual health in a way that combats taboos and misinformation. 

Clue Period Tracking mode was designed so that every person with a menstrual cycle could track and learn about their own unique cycle health. The mode takes the information you tracked and uses an algorithm to estimate your next period and ovulation day. It also allows you to track other physiological experiences like bloating, cramps, and sleep, so a person can see how patterns might relate to their cycle. 

The story behind Clue Birth Control mode

Throughout the continuous evolution of Clue Period Tracking mode, it became clear to the people who work behind the scenes at Clue that there was an unmet need for innovation in the birth control space. The search began for an effective, evidence based, side-effect-free birth control that had few barriers to access. As a result, Clue Birth Control was developed as a mode within the Clue app.  

How does Clue Period Tracking mode work? 

The algorithm for Clue Period Tracking mode was built to estimate your next period and ovulation date, and it does not make any predictions for your fertility. You can also track other data like how many hours you sleep, how motivated you feel, and more. The Data Scientists at Clue designed the Clue Period Tracking mode’s predictive capability using scientifically validated data from medical literature. Over time and with more data, the algorithm learns more about you and can provide you with more accurate experience, period, and ovulation predictions. In this way, the Clue Period Tracking algorithm is always evolving. 

The Clue Period Tracking mode is designed to give you more information about your body and its patterns over time. It isn’t intended to be used to prevent pregnancy and cannot safely help you predict all the possible days when you might be at risk for pregnancy. That’s where Clue Birth Control comes in. 

How does Clue Birth Control work?

Clue Birth Control is an innovative, non-hormonal, digital form of birth control. It is designed to use data about your cycle combined with millions of data points from landmark studies, to predict which days are high or low risk for pregnancy. When you track the first day of your period, Clue Birth Control uses this date to calculate your pregnancy risk for each day of your cycle. 

The United States Food and Drug Administration (FDA) cleared Clue Birth Control as a software application that can be used as a contraceptive to prevent pregnancy. Clue Birth Control received this certification after submitting extensive documentation about its efficacy, the research behind it, and the processes our team has in place to make sure the app is implemented safely and accurately. 

You will need to check the app each day before having sex that may result in pregnancy and use a barrier method such as a condom on high risk days. In this way, it requires frequent participation, just like when you take a birth control pill each day or put on a condom before you have sex. Unlike some other forms of birth control, it’s not a set-it-and-forget-it form of contraception.

How effective is Clue Birth Control?

When used perfectly, Clue Birth Control is 97% effective at preventing pregnancy (2). When it’s not always used perfectly, or used typically, Clue Birth Control is 92% effective (2). How do we know how effective Clue Birth Control is? Researchers at the Institute for Reproductive Health (IRH) at Georgetown University conducted a clinical trial on the algorithm Clue Birth Control is based on. This study followed 718 women in the United States of America for up to 13 cycles of use to determine the effectiveness of the Clue Birth Control algorithm to predict high risk and low risk days for pregnancy prevention. 

Why can’t I use the Clue Period Tracking mode as birth control?

The Clue Period Tracking mode uses science and your personal cycle data to predict when you have your period and ovulate. It’s science-based, but hasn’t been studied or validated as a type of birth control. That’s why Clue created the Clue Birth Control mode. It uses a different algorithm than the Clue Period Tracking mode to determine which days are high risk and low risk for pregnancy. Clue Birth Control has been validated and FDA-cleared as an effective form of birth control.

Clue Birth Control will be launched in the USA in 2022. We are excited to bring Clue Birth Control to other countries soon. This will take a little more time, but we’re on it.

an illustration of the Clue flower
an illustration of the Clue flower

Live in sync with your cycle and download the Clue app today.

You might also like to read

An arm wearing a ticking watch with blood drops.


What’s “normal”?: menstrual cycle length and variation

The menstrual cycle is more than just your period—it’s the rhythmic changes of the your reproductive system.

Popular Articles