Basal body temperature changes yield a lot of information about female hormone levels. According to Bongmi, Inc., the company that makes the Femometer, hormone changes two or three days after ovulation can cause a rise in basal body temperature (BBT) from 0.4 to 1.0 degrees. Consistent measurement with an accurate thermometer and tracking the results can give a woman a world of helpful information about her body and her menstrual cycle. Unfortunately, taking the temperature, recording it, and tracking it over time can be a hassle.

That’s why Bongmi developed the Femometer, a combination of a precise thermometer and an accompanying smartphone app, available for both iOS and Android phones. Basal body temperature is measured the first thing in the morning, before you get out of bed, using the Bluetooth-connected oral thermometer. The Femometer is accurate to plus or minus 0.09 degrees Fahrenheit, Bongmi claims. The BBT reading is automatically synced to a smartphone via Bluetooth, where the reading is recorded and charted.

Users can also track other pertinent information in the app such as the beginning and end of a period, cervical fluid, ovulation tests, sleep, emotions, weight, and medication. In addition, users can enter sleep amount and quality, emotions, exercise, and weight. The purpose of all the information along with BBT is to provide women with as much information as possible about how their bodies react during their menstrual cycles. The Femometer automatically generates a BBT chart and uses the data to predict monthly cycles. It can calculate the best days to get pregnant or avoid getting pregnant and produces a monthly calendar with ovulation date, fertile and infertile dates, and the expected start and duration of the user’s period.