Home / Blog / A Brief History of Basal Body Thermometers & FAM

A Brief History of Basal Body Thermometers & FAM

For as long as humans have existed (and reproduced), women have attempted to control fertility and possible conception with various means. This means that the history of fertility awareness is much longer than what can fit into a single blog post! Throughout history, women have used herbs and barrier technologies to avoid pregnancy, the positioning and rhythm of the moon to understand the timing of ovulation.

basal body temperature during pregnancy

"The Pill" - Introduction to Birth Control

However, in the 1950’s the birth control pill was introduced, and the world as we know it changed. While more and more women began working outside of the house, the pill allowed women to be able to delay the childbearing years. This gave a generation of women much more control over the timing of their families as well as growth of their careers. While the pill did advance the status of women, many people are beginning to question and ask, at what cost? Today, more and more people are looking for secular, non-hormonal ways to manage their fertility.

It wouldn’t surprise me if women knew long before scientists the times in the month in which pregnancy was possible, as women have always been innately connected to their bodies and to the cycles within themselves and nature. However, it wasn’t until the 1850’s in the UK when the connection between cervical mucus and conception was discovered.

We know now that different types of cervical mucus indicate the levels of estrogen and progesterone present. As estrogen rises, and ovulation approaches, the type of cervical mucus changes. Cervical mucus is also essential for conception as it facilitates sperm staying alive and reaching the egg.

In 1905 scientists correlated an upward shift in basal body temperature with the event of ovulation. That shift in basal body temperature indicates ovulation has happened due to the presence of progesterone warming up the body. Even further back in history, thermometers were first conceptualized in the 1500’s, with a more modern version of the thermometer created in 1709 by Daniel Fahrenheit.

The early thermometers were made with alcohol or mercury. Nowadays some people still use mercury thermometers as their basal body thermometer, with the most common options being digital thermometers, or even ones that sync via bluetooth with your smartphone. 

The Growth and Development of Basal Body Temperature 

30 years after the discovery of the shift in basal body temperature, a temperature-only method of birth control was created in Germany. Meanwhile, the calendar and temperature methods were endorsed by the Catholic church, which was instrumental in contributing resources and research towards the Catholic Natural Family Planning approach of fertility awareness.

In 1951 the Symptothermal method of fertility awareness was developed in Austria, combining both basal body temperature and cervical mucus for the full picture of fertility throughout the cycle. This was followed by the Billings Ovulation Method, a cervical mucus only method, developed in Australia. All of this was before the creation of the first hormonal contraceptives. 

Nowadays women are increasingly looking for mainstream methods of fertility awareness based methods. This means as technology expands, so do options for basal body thermometers and a new category of technology called “femtech.” It raises the question of introducing technology and apps into a very intimate part of our lives. There exists a fine balance between trusting our bodies, doing our own education and empowerment, and trusting apps.

In an ideal world, I believe that technology can enhance our body literacy, not replace it! After all, discovering the connection with basal body temperature and ovulation was one form of technology that increased women’s capacity to understand their bodies. As a fertility awareness educator apps and devices that enhance body literacy and don’t do the work for you, are ideal when it comes to fertility awareness.

Present Day: The Launch of Tempdrop

This leads us to the current day. More and more technologies that monitor our fertility and hormone levels are being developed and released, including apps and devices centered around women’s health. This includes Tempdrop, the wearable basal body thermometer, which was launched In 2017. Tempdrop and continues to grow and develop with more women using the device. This information can be empowering and help women feel empowered by, rather than burdened, by their fertility. 

The wonderful thing about tracking your fertility with basal body temperature is that it isn’t inherently complicated. While we know much more about fertility than we did in the 1850’s, the general idea of tracking basal body temperature and cervical mucus is the same. It requires you to get to know your body and the very basic cyclical rhythm of ovulation and menstruation. Thank goodness we now have technologies to make measuring this easier, like Tempdrop!

If you'd like to learn more about FABM, including how to chart your cycle, identify your fertility window, and be your own ovulation calendar, download Tempdrop's free Introduction to Fertility Awareness, a beautifully-designed guide written by seven certified educators (including Nathalie!).

Nathalie Daudet

Nathalie Daudet is a social worker and FEMM instructor based in Winnipeg, Canada. She discovered fertility awareness after searching high and low for a non-hormonal method of birth control. After learning the magic of fertility awareness and the gift of body literacy, she decided to pursue formal fertility awareness training and share the knowledge of fertility awareness with women looking for a natural birth control option. Fertility Awareness Project is the hub for Nathalie’s FEMM classes in both group and individual formats, online and in person in Winnipeg. If you love this post and would like to thank Nathalie, shop Tempdrop with Nathalie's unique referral link.