Frequently Asked Questions

Basal Body Temperature (8)

What is the definition of basal body temperature?

Family Planning: A Global Handbook for Providers, a 2012 WHO publication related to calendar-based contraceptive methods:

Basal body temperature – the body temperature of a fertile woman when resting – rises after ovulation and remains high until the next menstruation.

Detailed method: Every day after waking up, immediately (before getting up or eating any food) measure body temperature and record it in a special designed form; after ovulation, body temperature usually rises 0.2-0.5°C/0.36-0.9°F (this usually happens at the middle stage of the menstrual cycle).


Basal body temperature is the lowest body temperature attained during rest (usually during sleeping). It is generally measured immediately after awakening and before any physical activity has been undertaken.

Why does basal body temperature rise after ovulation?

The rise of female basal body temperature during the menstrual cycle is the result of progesterone stimulating thermal homeostasis in the anterior pituitary gland.

Why is measuring basal body temperature important?

Conception guidance

Progesterone in the female body peaks at ovulation and when the ovarian follicle develops into the corpus luteum after ovulation, so basal body temperature change (rise) indicates the day of ovulation. Considering the lifespan of sperm and egg, knowing when ovulation day can increase pregnancy possibility (possibility of conception is high five days prior to the day of ovulation, and highest two days prior to the day of ovulation).

Other gynecological usages

A luteal phase shorter than 12 days and a rise in body temperature of less than 0.3-0.6°C /0.54-1.08°F means inadequate luteal function.Luteal phase (basal body temperatures rising) lasting for more than 20 days without dropping is considered a sign of pregnancy.In the first three months of confirmed pregnancy, basal body temperature with a clear drop trend may be a sign of early miscarriage.In cases of an ovulatory DUB (dysfunctional uterine bleeding) or induced ovulation of infertile women, basal body temperature change can be used to determine whether ovulation has taken place.In cases of women with abnormal vaginal bleeding, it is difficult to accurately determine menstrual cycle based on menstruation. Measuring basal body temperature can provide an accurate and reliable indication of the menstrual cycle.If basal body temperature is too high in gynecological endocrine patients, the possibility of pelvic tuberculosis and endometriosis should be considered

What are the traditional methods of measuring basal body temperature?

Putting a thermometer under the tongue for five minutes immediately after waking up, recording body temperature number in a specially designed form, continuously measuring for one to three months while recording information on menstruation and cervical mucus, whether ill or not.

Since female basal body temperature only rises 0.3-0.6°C /0.54-1.08°F after ovulation, normal mercury thermometer is not accurate enough due to their margin of error of 0.5ºC/1.0°F, making it unsuitable for measuring basal body temperature. Many pregnancy preparation groups recommend using an electronic thermometer based on thermistor technology. Some thermometer manufacturers have added recording and charting functions to their basal body temperature thermometers.

What are the differences between iFertracker and traditional methods?

Worn overnight, the iFertracker collects a whole night of temperature data. And the advanced algorithm in the app provides the true basal body temperature, which is about 30 minutes before awaking. The app also records the daily reading and converts to BBT chart automatically. The user can easily understand the rise (ovulation day) from the chart and the notification of TTC in the app.

The data accuracy of the iFertracker makes it easier for doctors to evaluate basal body temperature and provide clinical advice. Clinical research shows that for women suffering from fertility problems while still having regular menstrual cycles, continuous measurement of whole-night body temperature predicts day of ovulation and ovulation cycle more accurately than ultrasonic monitoring of type-B follicle size.

Do irregular sleeping patterns affect basal body temperature?

A regular life routine leads to more regular progesterone secretion, which is good for preparation of ovulation and conception. Irregular sleeping habits may lead to progesterone secretion disorder, which affects menstrual cycle and ovulation. We suggest that you maintain a regular routine when trying to conceive, and that you wear the iFertracker regularly.

How is the Fertile Window calculated?

The adult menstrual cycle lasts 28-35 days on average. The follicular phase is the phase before ovulation, and the luteal phase is the phase after ovulation. The follicular phase often varies between 14-21 days; the luteal phase is normally consistent around 14 days.

The follicular phase is the phase before the day of ovulation. Taking into account the average lifespan of sperm and egg (sperm live for 3-5 days, eggs for less than a day), the fertile window is 12-17 days before the next menstruation.

How is the Fertile Window calculated?

The adult menstrual cycle lasts 28-35 days on average. The follicular phase is the phase before ovulation, and the luteal phase is the phase after ovulation. The follicular phase often varies between 14-21 days; the luteal phase is normally consistent around 14 days.

The follicular phase is the phase before the day of ovulation. Taking into account the average lifespan of sperm and egg (sperm live for 3-5 days, eggs for less than a day), the fertile window is 12-17 days before the next menstruation.

Does increasing frequency of sexual intercourse during the fertile window increase pregnancy possibility?

Having sexual intercourse every two-three days gives the highest chances of conception. However, it is not clear whether increasing the frequency of sexual intercourse raises the chances of conception during the fertile window.

Medical research suggests that frequent sexual intercourse lowers sperm count and volume, but increases sperm quality. By having sexual intercourse every two days in the fertile window, male partners can not only save energy but also ensure their sperm count remains high. Sperm count is the key factors for conception.

Product (8)

What is the iFertracker?

The iFertracker is a wearable thermometer used to measure basal body temperature, a measurement used to predict the ovulation date and fertile window for women who are trying to conceive.

What does the iFertracker do?

By wearing the iFertracker while sleeping, then syncing it with the iFertracker app on a mobile device in the morning, women can measure their basal body temperature, which is the lowest body temperature during sleep, attained in a stable state during the whole night. The iFertracker app converts the daily basal body temperatures into graphic form to reflect the BBT change before and after ovulation occurs. The app informs users the current stage of their menstrual cycle, records relevant events, reminds them to take medicine, and predicts the timing of ovulation. This helps women to plan sexual intercourse to get pregnant and manage their menstrual cycle in a smart way.

Who should use the iFertracker?

Women in reproductive age who are trying to conceive. The iFertracker can be used before or during pregnancy, to prepare for pregnancy, and to monitor the risk of miscarriage.

Is it safe that the iFertracker directly contacts the skin?

Completely! The materials used for this product meet biocompatibility and RoHS standards.


01.a. The product has passed tests on cytotoxicity, irritation, skin sensitization, and meets the requirements of “Biological evaluation of medical devices — Part 5: Tests for in vitro cytotoxicity.” The product has passed tests on “Biological evaluation of medical devices -Part 10: Tests for irritation and delayed-type hypersensitivity.

02. ”The product complies with Rohs2011/65/EU requirements. It also complies with the requirements of EC 62321:2008″ Electro technical products—Determination of levels of six regulated substances (lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls).”

Does the iFertracker emit radiation?

The iFertracker does not connect with the app while worn. The iFertracker uses Bluetooth 4.0 (Bluetooth low energy) technology when syncing data in the morning,  meaning it emits far less radiation than a mobile phone. It fully complies with electromagnetic radiation standards.


Please refer to WHO: Electromagnetic fields and public health: Mobile phones

Are the patches safe?

In order to guarantee the best user experience, we tested about 80 different types of patches and chose the adhesive patch from well-known brand 3M. On top of this, we reduced the area of skin contact with the patch, designing a circular double-sided patch for the best wearing experience.


We recommend that users use the adhesive patches we provide, and that the device be worn in the environment of room temperature. We recommend it not be worn for more than 24 consecutive hours on the same spot. The patches provided with this product are hypoallergenic. However, if skin irritation occurs, stop using the iFertracker immediately and refer to your doctor for other adhesives.

How accurate are the measurements?

The accuracy of the iFertracker is:

±0.05°C (35-38.5°C)

±0.1°C (25-34.99°C, 38.51-45°C)


±0.09°F (95°F-101.3°F)

±0.18°F (<94.9°F and >101.3°F)

Why might the iFertracker have different results from other thermometers?

01.  Temperature measurement results vary depending on the part of the body used, though all are supposed to be close to the internal core temperature (what we describe as body temperature). Traditional basal body temperature measurement entails using a thermometer orally. The iFertracker basal body temperature thermometer measures axillary (armpit) temperature. Oral measurements give a higher result than axillary temperature; clinical research shows a 0.5°C /0.9°F difference between armpit temperature and rectal temperature, and a 0.74-1.34°C /1.33-2.41°F difference between ear temperature and rectal temperature.

02.   Taking your temperature at different times leads to different results. Traditional basal body temperature is taken immediately after waking up, while the iFertracker measures it during sleep. (True basal body temperature is about 30 minutes prior to waking).

03.  Different thermometers give different results. Mercury thermometers allow for a margin of error of +0.10°C to -0.15°C /+0.18°F to -0.27°F, while the iFertracker, within the normal temperature range of a human body (35-38.5°C /95-101.3°F), has a margin of error of only ±05°C /±0.09°F.

Apps (3)

Which iOS mobile phones and tablets support the iFertracker app?

All iOS devices with Bluetooth 4.0 or above, and iOS8.0 or above

Where can I download the iOS app?

Can I use the iFertracker with Android?

No. Unfortunately we no longer offer the iFertracker app on Android/ Google Play.

Manual (19)

How to use the iFertracker…

The iFertracker is worn under the armpit before the user goes to sleep and taken off when upon waking up the next morning. The iFertracker syncs its data with the iFertracker app on a mobile device via Bluetooth in order to provide daily basal body temperature measurement.

How is the iFertracker turned on and off?

After putting in the battery, hold the iFertracker in your hand until the LED indicator blinks once a second. (The first time you use it, you will need to connect the iFertracker with the app on your mobile device to sync the time). If the battery has enough power, you don’t need to connect with the app beforehand except the first time; you can simply wear it, and the iFertracker will automatically turn on. After removing it in the morning, put the iFertracker aside at room temperature. When the device senses the drop in temperature, it will turn itself off automatically.

What is a firmware update?

In order to improve the function of iFertracker firmware, we will provide updates to the iFertracker device when needed. The iFertracker app will notify you once the firmware update is available. The update will be done by opening the iFertracker app on your mobile device and following the instructions.

How are the patches used?

Peel off the white side of the patch and stick it on the side with metal part (the temperature probe) and Raiing logo.  Make sure the patch does not go beyond the border of the sensor, then peel off the transparent layer of the patch and attach the sensor to the armpit to begin tracking temperature.

What is the correct position of the iFertracker?

The metal part of the sensor should firmly contact the skin inside the armpit. Shave your armpit before wearing and ensure that when the arm is held tightly to the side, the armpit covers the whole iFertracker.

What should I pay special attention to while wearing the iFertracker?

01.  For a more comfortable wearing experience, we suggest that you shave your armpit before using the iFertracker.

02.  Wear the iFertracker for a minimum of four to six hours a night, during sleep.

03.  Basal body temperature data will not be collected if you wear the device less than 4 hours a night or wear it too low in your armpit

What should I do if the iFertracker comes off while I sleep?

Put it back in the suitable position in your armpit if this happens. However, if the iFertracker is out of your armpit longer than 30 minutes it will not be able to find the lowest body temperature point in a stable sleep state. As a result, when you sync to your app, it will tell you that the basal body temperature has not been recorded. If your device falls off frequently, we suggest you change patches, shave your armpit, and clean skin with water or medical alcohol before wearing.

What happens if I forget to use the iFertracker?

However, if it happens during a time outside your Fertile Window, it most likely will not impact the predictions in a meaningful way.

Will the temperature measurement be affected if I use the bathroom at night?

No. The iFertracker automatically filters the disruption when you use the bathroom at night.

How do I sync data?

Syncing data is very easy. You only need to take off the iFertracker and place it next to your mobile device with the iFertracker app open. Wait for the data to upload automatically and the BBT reading will display at the end of data processing.

Do I need to sync with the app every day?

We suggest that you sync the iFertracker with your iFertracker app on the mobile device with Internet access every day as soon as you wake up. This ensures you get the result of the data analysis as soon as possible, and find out what your basal body temperature is that day. Syncing data daily is especially important around the dates of ovulation to alert you in real time when you will be ovulating. However, the iFertracker saves data for up to 10 days, so if you don’t have time to sync every day, you can find a convenient time to sync multiple days in one go.

What is the LED indicator for?

A single blink at one-second intervals indicates that the 01.  iFertracker needs to be connected with the mobile device in order to sync data.

02.  A single blink at four-second intervals indicates that the iFertracker is on.

03.  The LED remaining lit indicates low power and that the battery needs to be replaced.

What is the power supply? What is the battery life?

CR2025 watch battery in room temperature will last 45 – 60 days at 8 hours per day usage; however, firmware updating and frequent data syncing with app may deplete power more quickly.

I’m pregnant already. Do I need to continue wearing the iFertracker?

We suggest that you continue wearing the iFertracker for two to three months after becoming pregnant. During the first eight weeks of pregnancy, your progesterone level mainly depends on a section of the ovary called the corpus luteum. After eight weeks, the placenta gradually takes over. Basal body temperature can be used to measure your progesterone level. During the early stages of pregnancy, a sudden drop decrease in corpus luteum function may result in miscarriage and can be captured by decreased BBT. Corpus luteum function can be tracked through basal body temperature. This means that monitoring basal body temperature throughout pregnancy can help you pick up early signs of a risk of miscarriage and take actions accordingly.

What is the meaning of the color on the BBT chart?

Pink represents the period of menstruation. Yellow indicates the best timing to try to conceive. Orange represents the date of ovulation. Blue is the safe period, during which the chance of conception is low.

What should I do if, when I first log in, I don’t remember the date of my last period?

Use your best estimate.


The date can be changed after you input it. However, the app requires a start date for at least one menstrual cycle, so if you have only input the initial start date of one menstrual cycle, it cannot be deleted.

Why do I need to input menstrual cycle and period length?

This information creates a database that allows the iFertracker to recognize different stages of the menstrual cycle and predict ovulation date. The changes in color on the calendar and the BBT chart correspond to this information.

Why do I need to record relevant events?

Using basal body temperature as a guide to conceive requests information such as sexual activity, sleeping quality, and mood, etc. The app can provide more accurate predictions of ovulation date with all relevant information inputted into the log.

How do I record relevant events?

1.Click on the   on the right of the Daily Status page, and choose from the list to start to record;

2.Click on the Calendar icon on the top right of the Daily Status page, choose the specific date on which the event occurred, then click the  on the bottom to input the record.

3. Enter the BBT page, choose the specific date on which the event occurred, then click the   on the bottom to input the record.

Troubleshooting (4)

I can’t turn on the iFertracker.

01.  After you hold the iFertracker in your hand for a few seconds, the blue LED on the battery compartment side should begin blinking to indicate the power is on.

02.  Battery may be low on either the iFertracker or your mobile device. Try changing the battery (CR2025 battery) or charging your mobile device.

03.  The battery may have been used up very quickly due to low environmental temperature. Try changing the battery (CR2025 battery).

04.  Take out the battery, wait for one minute, then put the battery back and try again.

05.  The electronic components in the iFertracker may need to be reactivated. Take out the battery, then put it back in the chamber with the plus-symbol side facing down. After a moment, replace the battery with the plus-symbol side facing up.

06.  On the iFertracker app, click on the Feedback icon in the More >Help menu and explain the problem you have encountered. We are here to help.

I can’t connect the iFertracker with my mobile phone/iPad.

01.  The Bluetooth function on your mobile phone/iPad may not be switched on or may not be working normally. Try switching on Bluetooth or restarting the mobile phone/iPad. Note that you should turn on Bluetooth and pair the iFertracker thermometer by opening the iFertracker app. You will not see the iFertracker listed in the Bluetooth system menu.

02.  The app may not have launched properly. Please quit the app then launch it again, or delete it and download it again.

03.  The iFertracker may be out of the Bluetooth range from the mobile phone/iPad. Put the iFertracker closer to the mobile phone/iPad to see if they connect with each other.

04.  The iFertracker thermometer may be connected with another mobile phone/iPad. If so, disconnect and try again.

05.  On the iFertracker app, click on the Feedback icon in the More >Help menu and explain the problem you have encountered. We are here to help.

The iFertracker won’t sync data or show basal body temperature normally.

01.  This may be because, after changing the battery, you began using the iFertracker without first connecting to your mobile phone/iPad to sync time. Start the iFertracker app and sync the time with your iFertracker on your mobile phone/iPad first, then quit the app and begin using the iFertracker. 02.  This may be because the measurement time is too short. You need to wear the iFertracker for at least 4-6 hours to enable analysis of daily basal body temperature.

03.  The iFertracker may not be in proper contact with the skin. Adjust the wearing position, shave your armpit before wearing, and make sure the metal probe is firmly in contact with the skin under your

04.  Battery may be low. Change the battery and try again.

05.  If the environmental temperature is too low, the iFertracker may stop working. We suggest syncing data immediately after taking it off in the morning, or holding the iFertracker in your hand for a few seconds to warm it up. When the LED blinks, it is ready to sync.

06.  The iFertracker may have accidentally connected with the app while you were wearing it, and data has been uploaded. When wearing the iFertracker, make sure the app is off, or turn off the mobile phone/iPad itself.

07.  On the iFertracker app, click on the Feedback icon in the More >Help menu and explain the problem you have encountered. We are here to help.

The power is low from the start.

(This refers to a specific battery issue some users have experienced in winter without room heating system.)

The CR2025 battery used by the iFertracker cannot cope with low temperatures. The combination of low room temperature and the iFertracker’s auto on/off function causes the battery to be drained very quickly.

If your room temperature is below 20℃/68℉, keep the battery in a warm place (above 20℃/68℉) for at least an hour or hold the battery in your hand for 5-10 minutes before using, and sync data immediately after taking the device off in the morning. If the battery is already in the device, hold the iFertracker in your hand for 15-30 minutes before syncing data.

Purchasing, Return, and Exchange (4)

What is the exchange/return policy?

If you purchased your iFertracker through or Amazon our return window is 15 days from the date of delivery.

If you bought the iFertracker from a different vendor please consult the original vendor.

For questions on returns contact us at

What do I do when the battery runs out?

Simply buy the same type of watch battery (CR2025).

Don’t have iFertracker? Get started!