Phone:+43 316 23 200 420

Our office hours are Monday to Friday 8am till 5pm (CET).

How to correctly apply and use the femSense patch

Emma explains femSense step by step. Emma will also guide you through our App.

Get started with the patch

How do I find out if my smartphone has NFC?

Apple: iPhone 7 or newer models have the sufficient NFC functionality. NFC is automatically activated, you do not need to turn it on or off Remark: iPhone 6s has the NFC function, but it is restriced to Apple Pay


  • Drag the status bar down and look for the NFC Button
  • Open the settings, go to “Connectivity” or “Device connectivity” and look for a slider to activate NFC
  • Go to the webpage of the manufacturer of your smartphone and look for the specifications of your device

Additonal information: If you are unsure that your smartphone has NFC, click this Link


How long must I wait before I can apply my first patch?

femSense calculates the first time you apply a patch based on your personal cycle data. That means that you may have to wait two or three weeks before you can apply your patch. This is because you may have already ovulated in your current cycle and femSense can no longer detect it. Tip: Start femSense Kinderwunsch Ovulation in the app as soon as you receive your patches so you wont miss a single day!


THe app has advised me to stick on the patch, what do I need to do?

Before you apply the patch you should clean the area under the arm, where you want to stick the patch, with a non-greasy soap or shower gel and dry the area thoroughly. Please do not use deodorant prior to applying the patch. The adhesive power of the patch can be affected if not applied correctly.


How do I open the individual package?

When holding your individual package against the light, one of the short sides has rills, whilst the other is plain. Grab the lashes on the plain side and pull them apart, then you can safely take out the patch.

Hint: When you see a perforation, you can open the individual package by tearing at the perforation


How do I activate my patch

If the app notifies you that today is the day to apply the patch, you have to activate it in the Kinderwunsch Ovulation function screen. How to activate the patch

For iOS:

Step 1: Slide the top edge of the back of your iPhone onto the patch until you feel a vibration, hold your phone in this position for about 3 seconds until the app confirms it has connected with the patch.
Step 2: Please read the patch once, so that the app can confirm the that the patch has been activated.

For Android:

Step 1: Please first ensure that you have turned on the NFC function on your smartphone.
Step 2: Slowly slide the back of your phone over the patch until it vibrates and hold it in this position for about 3 seconds. The app will confirm that the patch has been activated.


How often must I read the patch

The patch should be read at least once a day, we recommend reading the patch in the morning within a couple of hours of getting up. The patch can be read a second or third time during the day but if you miss a reading, valuable temperature data could be lost, and ovulation detection becomes less accurate. If you forget a reading the app will remind you with a push-notification (if notifications are switched on).


How long do I have to wear the patch?

The length of time you wear the patch varies from person to person depending on when we calculate your ovulation, 7 days at most.


I forgot to read my patch today – what do I do?

No problem, as soon as you realise that you forgot to do a reading just do one at the next possible opportunity. We can still use the collected data to calculate the time of your next ovulation. During your next cycle, be sure to follow the reminders on the app.


What do I do if I have a problem with the app or the patch?

The best way is to go to the femSense app and click on “Contact Support” in the menu. If you have problems with the patch, you can get a patch read out here and the mail program installed on your smartphone will open automatically. You can then report your problem to the femSense support team, send the logs from your app and information from the patch.


Where is the NFC antenna in my smartphone?

This varies depending on the manufacturer. Here is a list of links where you can find out where the NFC antenna is installed in your phone.

  • Apple Devices (iPhone and higher): The antenna is usually located in the frame at the top of the phone.
  • Samsung
  • Huawei
  • HTC first choose your smartphone model, then click on Connectivity -> Wireless Sharing -> Using NFC
  • SONY Choose your model then click on User Guide -> Connectivity -> NFC.
  • LG
  • Nexus
  • Pixel
  • One Plus: The atenna is usually located near the camera.

femSense Ovulation


What is femSense Ovulation?

femSense Ovulation is an Ovulation Deection system which helps women plan a pregnancy. It is a Class 1 medical device which has a CE marking. It is the first intelligent adhesive patch used to determine the most fertile days during your cycle, in a simple and natural manner.


How does femSense Ovulation work?

femSense Ovulation is an “intelligent” plaster with an integrated chip. It is used in combination with an app which monitors your cycle. The adhesive patch is stuck on under your arm where it continuously measures your body temperature over a few days. The patch has to be read by your smart phone once a day. The reading is done by NFC, a data transfer method you will be familiar with from contactless payment at the supermarket. femSense can precisely detect your ovulation based on the body basal temperature curve and can then predict your next fertile window. The app will remind you when to stick on the next patch and when you are particularly fertile.


Who can use femSense Ovulation?

femSense Ovulation is for women of childbearing age with menstrual cycles of 28 +/-7 days. Intercyclic fluctuations of cycle duration should not exceed +/-3 days. If you have an irregular cycle femSense Ovulation cannot work accurately, we recommend therefore consulting a doctor before using femSense Ovulation if you have very irregular cycles. Certain medical conditions prevent femSense Ovulation from reliably predicting ovulation. These include:

  • Severe, acute or chronic diseases
  • Heavy consumption of drugs, alcohol or nicotine
  • Oligomenorrhea (infrequent menstrual periods)
  • Polycystic ovary syndrome (PCOS)
  • Obesity
  • Hirsutism (excessive hair growth)
  • Plaster allergy

How does femSense Ovulation differ from existing products?

What sets femSense Ovulation apart from all other products on the market is our technology. femSense has developed a sensor, encapsulated in an adhesive plaster, which unobtrusively and noninvasively precisely measures the basal body temperature at regular intervals and can therefore accurately identify the exact time of ovulation. femSense is precise and user friendly. The medically certified, wafer-thin patch is worn only for a few days during the cycle and has no effect on the quality of life.


Can I use femSense if my smartphone does not have NFC?

No, the femSense patches can only be read out via NFC.


What can affect my body temperature?

Illness, intense physical activity, consumption of alcohol and very irregular sleep (due to stress, jetlag or shift work ) can affect your body temperature. When you have long lasting disturbances in your body temperature (due to fever or stress), we recommend to wait until the next cycle to apply a path. Short term disturbances have no impact, since your body temperature is measured continuously throughout several days.


About the Product/ How to use

How big is the patch?

65mm x 60mm


What is the patch made of?

The patch comprises of certified biocompatible materials usually used medically in wound treatment. A battery powered thermal sensor is encapsulated inside the patch in a waterproof seal.


How often can I use the patch?

The patch is only used once. After use remove the patch and dispose of it in the battery recycling bin.


Will other people know when I am using femSense?

Not unless you tell them. The femSense patch is very discreet. It is a nude colour and is applied directly onto the skin under your arm. There is also no branding on the patch so that even if it can be seen it could just be a normal plaster.


Is the patch comfortable?

Yes. The patch is small, skin friendly and made of certified biocompatible materials usually used medically in wound treatment. After the patch has been worn for a few days you may need to apply a skin care product to sooth and rehydrate the skin.


Can the patch cause skin irritations?

Because the patch must be worn over several days and because of the adhesive strength of the patch, slight skin irritation, itching, burning or redness may occur. This should however disappear within 48 hours at the latest. If the skin irritation persists for longer than 48 hours, please consult a dermatologist.


Can I shower or have a bath while wearing the femSense patch?

You can wash or shower as normal however baths or saunas while wearing the patch are not recommended.


Does femSense show me my temperature curve?

No, femSense processes and analyses your temperature values exclusively internally in order to exactly identify your ovulation. Temperature values or curves are deliberately not displayed, as femSense Ovulation Test is not intended as a diagnostic tool for analysis or detection of diseases or other medical conditions.


Can I take a cycle break from femSense Ovulation?

Yes. If you want to pause the femSense Ovulation for a cycle that is no problem. Just ignore the Kinderwunsch Ovulation function for that cycle and use the normal cycle tracker function, the Kinderwunsch function stays active in the background and is ready to start again at the beginning of the next cycle.
If you have taken a long break from the femSense Kinderwunsch Ovulation function you can restart it by scanning a patch.


Ordering femSense Ovulation patches

Where can I buy femSense Ovulation patches?

femSense Ovulation patches are available from our Webshop and from the app


Which countries does femSense deliver to?

Currently femSense delivers within Europe.


How long does the shipping usually take?

This depends from where you order the patches. Shipping to Austria usually takes 2 to 5 business days, international shipping takes 3-7 business days



Why do I have to enter my height and weight?

Both aspects influence your fertility. A too high or too low Body-Mass-Index (BMI) can result in an imbalance in your hormones.



Can I use femSense Ovulation when I am sick?

That depends entirely on the type of sickness. If you get sick while wearing the patch you should of course take it easy. If you have a fever, we recommend that you skip this cycle. If you are unsure, please consult your doctor.


Can I use femSense Ovulation if my cycle is irregular?

femSense Ovulation works best with regular cycles You may find that your periods typically occur every 21 to 35 days. Periods that are closer together or further apart aren’t always cause for concern. You have irregular periods if the length of your menstrual cycle keeps changing with regular deviations of more than 7 days. If your cycle is irregular we recommend that you consult a doctor when you plan on starting a family.


Up until recently I was taking the contraceptive pill, when can I start using femSense Ovulation?

Your body will need some time until your hormone balance has reestablished itself. You should allow up to 3 months for your natural menstrual cycle to fully re-establish itself. The first period after stopping the pill is known as a “withdrawal bleed”. The next one after this is your first natural period.The general rule is: you can use femSense Ovulation after your first natural menstruation when you stop taking the pill.


My skin reacts allergically to the plaster. Can I still use femSense Ovulation?

We use a certified biocompatible, medical, skin friendly plaster. If you are uncertain, please consult your doctor.


Safety/Security and Hygiene

Does the patch cause harmful radiation?

No. Unlike other products on the market which use, for example, Bluetooth for their data transmission, the femSense patch does not continuously transmit. Thanks to NFC technology data is transmitted for less than 2 seconds and only during the reading.


How hygienic is the application?

Because they are only used once the femSense Ovulation patches are particularly hygienic. You can maintain normal personal hygiene routines while wearing the patch - shower and use deodorant.


How secure is my personal data?

Your personal data belongs to you, your data is encrypted and anonymized for processing. We do not forward the data to others.


femSense Cycle Tracker

Why do I need a cycle tracker?

For practical reasons it is always useful to know when your period is due. Planning trips, activities, work events or appointments around your cycle makes sense and makes life easier. But there are also other advantages, recognising the connection between moods or ailments and a time in your cycle can increase your self-awareness and self-confidence.


Does a cycle tracker have any health benefits?

An understanding and awareness of your menstrual cycle can definitely have health benefits. Irregularities in your cycle can be an indicator of other health issues which can then be addressed. Making the connection between regular symptoms and your menstrual cycle can also be a revelation. Those sad days or bouts of anxiety are not as alarming when you realize they might be symptoms of PMS and therefore perfectly normal. Mood swings, tiredness, bloating, anxiety, depression, irritability, headaches and joint or muscle pain are all symptoms which are concerning when you don´t know the cause but are less worrying when you can identify them as PMS.


Will a cycle tracker help me get pregnant?

Monitoring your menstrual cycle will help you identify your most fertile days. However, if you are ready to start a family, we recommend femSense Ovulation, our Ovulation Test system. femSense Ovulation combines the femsense cycle tracker with a high precision temperature sensor to accurately identify your ovulation and therefore the perfect days to get pregnant.


How do I use the femSense Cycle Tracker?

femSense Cycle Tracker is an app with which you can monitor your menstrual cycle and general well-being. Once you have downloaded the app you enter a number of personal statistics which the femSense App then analyses and uses for its predictions. The app learns from you, the more information it has at its disposal the more accurate the predictions. This personal information can then also be gathered and used by the Kinderwunsch Ovulation app, a conception support app, which in combination with sensor patches can give a very accurate prediction of fertile days.


How do I enter the data?

  1. Go to the calendar
  2. Tap on the day you want to add something to. The window will open showing all the information you have already entered.
  3. Tap on the + in the lower righthand corner.
  4. Tap on the icons you want to add or move the slider to record symptoms

How do I change or delete information?

  1. Go to the Calendar
  2. Tap on the day you want to change the information you already entered.
  3. Click on “delete entries”
  4. Tap on the + in the lower righthand corner and change individual symptoms or put the sliders you want to reset back in the middle. You can also delete your notes.

How do I tell the femSense app that my period has begun or ended?

femSense predicts the beginning of your period but needs your confirmation that menstruation has actually begun. The confirmed date will then be shown in a darker pink in the calendar.

  1. Go to the calendar.
  2. Tap on the day on which your period started.
  3. Tap on the + in the lower righthand corner.
  4. Select a position which best describes how heavy your period is.

How does femSense make its predictions?

femSense uses an algorithm to continuously analyze your relevant input and make accurate predictions for you personally. At the beginning femSense forecasts your next period based on the average length of your cycle, the more information the algorithm has, the more accurate the prediction. The forecast menstruation and the forecast fertile days are highlighted in a light colour. As soon as your period has ended, and you have confirmed the beginning and end of your menstruation, the app will reset the highlighted days correctly.


Why don’t I see any prediction?

The last entry for your period was too long ago, therefore femSense cannot calculate your future cycle. Tip: Update the days of your last period in the calendar afterwards.


Can a single unusual cycle alter my predictions?

Your body reacts to various different external influences like sickness, stress, or jetlag. It is also perfectly normal for a woman not to ovulate during some cycles. Don’t worry, the femSense algorithm detects conspicuous deviations and excludes them from its calculations.


I just bought a new Smartphone, will I lose my existing data?

No. Your data is stored on our server. You can download the app to your new phone, log in with your password and access all your personal data again.


Can I use a cycle tracker as a form of contraception?

femSense cycle tracker is NOT a form of contraception.


femSense in General

Who is femSense?

femSense is an ambitious team led by founder Werner Koele, a biomedical technician and father of two boys.


Does the femSense App work on iOS and Android systems?

femSense works on iOS 13.0 or higher, on iPhone 7 or newer devices and on Android from OS 6.0 Marshmallow on smartphones with Near-Field-Communication (NFC) capable technology.


What is NFC and how does it work?

NFC (Near Field Communication) is a method of wireless data transfer. It enables two electronic devices, one of which is usually a portable device such as a smart phone, to communicate with each other. In order to communicate the devices must be with 4cm of each other. NFC is best known from contactless tap-and-go payment systems. NFC is a built-in feature in most smartphones.


How do I delete my femSense account?

If you wish to delete your femSense account, please use the “contact support” function in the menu of the femSense app and state that you wish to delete your account. Your account will be deleted within 2 working days.