BBT- what is it ?

Megan Martens
Feb 2, 2024
2 min read

While starting out on my journey to gather more knowledge on the menstrual cycle , to pass onto my daughter (9 at the time) who had started asking questions that I found I could not answer with confidence, either because I didn’t really know or I wasn’t sure how to tell her (was she old enough?) I came across BBT.

BBT - Bassal Body Temperature.

BBT is tracking your temperature first thing in morning when you first wake, while your body is still in state of rest. While you are sleeping, your core body temperature naturally drops, and this resting temperature is called your Basal Body Temperature (BBT).

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BBT allows women to clearly see when in their cycle they are ovulating, this is important for many reasons including:

Contraception
Regulating menstrual cycles
Track progress of hormone support
Fertility
Hormone balance

Women who have natural menstrual cycles have a bi-phasic (2 phase) BBT pattern, meaning their BBT goes through two phases.

This first phase is in your follicular phase- from day 1 of your menstrual cycle (first day of bleed) to ovulation (around day 15-20). Your temperature is naturally lower at this time.

The second phase follows ovulation (the Luteal phase), when progesterone is released from the corpus luteum, stimulating a rise in BBT. Tracking this ovulation can be very helpful to determine what is going on with your cycles and to track ovulation for contraception or fertility purposes.

I started to take my temperature each morning, more so to try it out and see my own body’s pattern and track it. Some mornings I forgot. Some mornings I took my temp after I had already got out of bed. Eventually I got into a swing, keeping my thermometer at my bedside for easy access in the morning and to remind me!

I tracked my BBT over several months to allow my pattern to be seen, and now that I have got myself into a routine of “tracking” which I found easier having it attached to a physical routine of having to check my temp, I am tracking different observations I have noticed as I become more aware of my body , womb and cycle. Noting things like bleed days, pain, mood, cervical fluid.

How do I do it?

Tracking is easy, all you will need is a digital thermometer.

Once you have this, pop it next to your bed, and every morning when you wake up, (before you get out of bed!), take your temperature and record it in a chart.

What do I use?

If Basal Body Temperature Tracking is something you would like to try too, choose a thermometer. For most people, it is beneficial to get the hang of tracking your temperature with a normal Thermometer that you get from a chemist. Hopefully it becomes a habit and part of your life too!

I recommend starting with a basic digital thermometer: Chemist Warehouse - 2 Decimal places for Basal temperature tracking.