How to Track Your Fertility Window with Basal Body Temp (BBT)

Jan 14, 2021

Trying to conceive or looking for a hormone free birth control? Basal body temping (BBT) might be for you! At my acupuncture practice I always recommend that my fertility patients track their BBT. It is a very easy way to capture a woman’s ovulation window. Also, there is oodles of TCM information within those daily temperatures. It really helps to guide treatments and hone in on what part of the cycle needs to be supported. Oh yeah, and it’s free!

The Cycle Basics

Starting with the very basics, a woman’s cycle “should” be within 28-32 days. Day one is considered to be the first day of your period. Day one, is the start of the follicular phase. During this phase the uterus will bleed 2-7 days. Then roughly mid-cycle ovulation should occur. Post-ovulation is considered the luteal phase of the cycle, until the period arrives and the cycle starts all over again. Got it? Simples? Cool!

Each phase of a woman’s cycle has a specific temperature range that a fertile woman “should” be ranging within. BBT charting is helpful because it captures these specific temperatures on a day-to-day basis. Making it helpful to see if a woman is actually ovulating, and on what specific day that might be occurring. Not kidding, some fertility patients are just timing sexual intercourse during the wrong days of the month. BBT charting is a clear indicator of a woman’s ovulation window.

Temperature Ranges (Follicular Phase, Luteal Phase + Ovulation)

Temperatures should be within their specified ranges during the follicular (97.0 – 97.6 degrees) and luteal phases (98.0 – 98.7 degrees). Taking your BBT daily will help to show if one of the phases needs some extra support. For instance, since we know progesterone spikes during the luteal phase, if a patient’s BBT does not rise (or even drops) then it is a clear indicator that progesterone needs some attention. 

If the chart shows no clear mid-month temperature spike, further evaluation may be required in order to determine if ovulation is actually occurring. A woman is fertile for a five day window leading up to ovulation. The closer to ovulation the higher the chances of conception. The day after ovulation occurs there should be a spike in the BBT. Approximately into the 98.0 degree range. The day following, the BBT will drop, and then a day (or so) after it will rise again. The second spike into the 98.0+ degree range indicates the beginning of the luteal phase. 

Above is an example of a clear ovulation spike

After a few months of consistent charting, you should be able to see clear indicators of your fertile window. The two BBT spikes are clear indicators that ovulation has occurred. If you are using the BBT method as a form of birth control, look for ovulation and know your fertile window is roughly 5 days leading up to ovulation. Course, it’s worth saying that no form of birth control is 100% effective. Let’s not be fools about this! If you DO NOT want to get pregnant then don’t take your method of contraception lightly.

How to Chart BBT

To begin, you will need a proper BBT thermometer. You can’t just use a regular thermometer. Every degree matters, BBT temping is very precise. You can pick one up an any drugstore. They are usually appropriately stocked next to the condoms or the pregnancy tests. Of course! Second, you can either chart old school style with a pen and a BBT chart piece of paper, or you can download one of the many BBT Apps. Personally, I love Kindara. It’s straight forward and super easy to use!

That’s all you need for supplies. So, let’s start charting! The key is to take your temperature as close to the same time as possible every-single-morning. Your alarm goes off, you reach for the thermometer. DO NOT GET OUT OF BED. Take your temp just as you wake; hence why it’s called “waking temp”. It’s also best to put the thermometer in the same spot under your tongue each day. Be concise with this. Chart it and go on with your day. After a couple months you should start to see a clear pattern.

Even though not every day is tracked (I get lazy) you can clearly see a Follicular Phase, Ovulation, and Luteal Phase

What Might Alter Your Temp

It is also important to know there are many factors that may alter your temp. For instance, you need to be asleep for at least 3-4 hours before charting. So if you wake to pee at 3am and your alarm goes off at 5am it’s not going to be accurate. Regardless, I still always encourage my patients to chart those mornings. That way they stay in the routine of waking to chart. Just simply make a note of the potential inaccurate temp in the App and move on. 

Other situations that might affect the accuracy of your temp is alcohol, caffeine, or not getting a sound night sleep (REM), or if you are sick. This is nothing to stress your head about though, just simply something to keep in mind. 

If you are interested in learning more details about BBT charting I highly suggest picking up Toni Weschler’s, Taking Charge of Your Fertility. It’s filled with all the BBT details and instructions one might need. Happy charting my loves!