femSense® works by using a smart patch that continuously measures body temperature to determine and confirm ovulation.

Here's how it operates:

You enter your cycle data in the femSense® app, and it prompts you when to apply the patch. The femSense® patch measures body temperature around the clock for up to 7 days per cycle. This data helps determine when you are most fertile.

Once the patch is applied, it does the monitoring, all you need to do is scan it with the femSense® app 2x per day. The femSense® app analyses the temperature data to predict and confirm your fertile days.

The patch is designed to be non-invasive and is made of medical-grade materials, making it suitable for sensitive skin and easy to use.

femSense® uses AI to learn from your cycle data over time, improving its accuracy and reliability in predicting your fertile windows .

femSense® will give you your seven most fertile days, and will confirm your day of ovulation. The app will give you resources based on your cycle data, supporting you throughout your cycle.

The femSense® smart patch tracks the specific changes in body temperature to confirm ovulation, providing a more precise and less invasive alternative to LH tests. Unlike LH tests, which predict ovulation based on hormone surges and require daily testing, femSense® offers 24/7, automatic temperature monitoring. This brings Basal Body Temperature (BBT) to the 21st century, and not only confirms that ovulation but also eliminates the daily hassle and guesswork associated with LH strips, making it a more user-friendly option for tracking fertility.

femSense® is suitable for fertile those who bleed and ovulate. If your cycle is between 21 and 35 days and your cycles don't typically differ more than +/- 3 days, femSense® is for you!

If your menstrual cycle is irregular, then femSense® cannot predict your fertile window reliably. In this case, we recommend you consult a doctor before choosing femSense®.

While we would love for femSense® to be suitable for everyone, it is important to note that this may not be the case.

If you have sensitive skin or allergies to medical-grade adhesives, the femSense® sensor patch may not be suitable for you. However, you can still use the femSense® app as a period and symptom tracker. 

Weight conditions (underweight or overweight) can increase the risk of adhesion issues or skin irritations with the patch. If you have a BMI lower than 18.5 or higher than 30, femSense® has not been tested for accuracy for you. 

Keep in mind, excessive consumption of nicotine or alcohol can impact body temperature and potentially affect the accuracy of femSense® in detecting ovulation. 

The algorithm bases its prediction of your fertile window on previous cycles and the patch is only worn for a maximum of 7 days during this time. If the patch has not measured ovulation in this time the app will notify you and ask you to remove the patch. This means if you have a very long cycle after a few shorter cycles the app could predict your fertile window too early, and the patch would not measure your ovulation.Regrettably, this means we cannot recommend femSense® for women with PCOS and therefore an irregular cycle. However, we have had several customers with PCOS who had phases of regularity for whom femSense® worked, which is why we say we cannot recommend femSense® for PCOS but every woman is an individual and even PCOS seems to be individual!

If you are unsure whether femSense® is suitable for you, please contact your doctor or get in touch with our technical support via e-mail to: customercare@femsenseus.com

You can use one patch per cycle. After applying and activating a patch according to the in-app instructions, the patch is associated with your current cycle.
 
You will need one patch per cycle that you plan to use femSense®. If your goal is to get pregnant, data from a recent study on women using natural family planning like femSense® can help you determine how many you might require:

• 42% conceived in their first month of trying
• 75% conceived by their third month 
• 88% conceived by six months 
• 98% conceived by 12 months

Recent user data suggests the average femSense® user in "Get Pregnant" mode uses 2.35 patches before reporting pregnancy (per September 2023 user data).

Everyone is different and femSense® cannot make any guarantees about when an individual may become pregnant, but we hope this helps!

The temperature sensor used in the femSense® patches detects temperature differences smaller than 0.1°C and was especially designed to detect the postovulatory temperature rise, which is typically between 0.2°C-0.5°C.

In contrast to the basic basal temperature measurement method the patch records a temperature value several times per hour. As the patch is always in the same position, measurement artifacts can be minimized. A clinical study with the medical university in Graz proved the accuracy of the sensor patch and now an independent Swiss statistics institute has confirmed that femSense® is 99.73% accurate when predicting ovulation.

femSense® is a FSA- and HSA-eligible product and, can be paid for on femSense®US.com with your FSA or HSA card.