Basal Body Temperature (BBT) is a powerful tool for women seeking to understand and enhance their fertility. Charting the BBT also provides important information about the state of hormones in your body. In Chinese medicine, we use the BBT charts of our patients to guide our treatment protocols, confirm and/or clarify our working diagnosis of the patient, and to provide feedback for treatment progress over time.
So what, you may be asking, is the BBT?
Your basal body temperature or your waking temperature, is exactly that; your body’s temperature first thing in the morning before any activity including, going to the bathroom, brushing your teeth or talking on the phone. In order to get a correct reading, you need to have been resting horizontally for a minimum of 3-4 hours. So if you get up to use the bathroom at 5:00 am, it is best to take the temperature then, unless you are planning to sleep until 9:00am.
Why measure your BBT?
Over time, the temperature readings provide an inordinate amount of useful information about your cycle, including: when you are ovulating, when you should expect your period, if you have conceived, and any potential problems in your cycle.
To be clear, charting for just one cycle will not provide this information. However, over the course of several cycles, you will gain clarity about how your reproductive system is functioning. Initially, the information that the chart provides is retrospective- only once the cycle is complete can we see what was going on. Charting for multiple cycles allows us to determine and predict your ovulation, and also see when something happens that is out of the ordinary.
Who should use the BBT method?
Any woman with regular or irregular cycles who is trying to conceive would benefit from charting her BBT. For women who are not having periods, I usually only have them chart for one month at the most. Typically their temperatures remain the same every day, but charting for one month will confirm that.
How to measure your BBT?
Pretty much any digital thermometer that has a tenth digit will work. There are some fancy basal body thermometers out there that measure to the hundredth, but truthfully, measuring your temperature to the tenth degree works just fine. I typically suggest to my patients that they get a digital thermometer that has a memory and a light. The memory function is helpful if you forget to record your temperature right away. The light is helpful if you do want to record the temperature, but the room is too dark to see the thermometer reading. Anything to make the tracking easier!
What is a normal temperature?
We have all been told that normal body temperature is 98.6 F, but when measuring BBT, often the temperatures are lower than that. There is nothing wrong with you or your body- that is just how your body is! The other part is that your BBT changes throughout your cycle, depending on where you are in your cycle.
What happens if I wake up earlier than normal?
The ideal way to chart your BBT is to take your temperature at the same time every day. However, we all know that sometimes that just won’t happen. Maybe you will have to get up extra early for a meeting, or on the weekend you want to sleep in. That is all perfectly fine! When you chart your temperature, make a note of what time you took your temperature, because you can factor that into your charting. The general rule is that for every half hour later or earlier that you take your temperature, it will vary by .10 degree. If you typically take your temperatures at 7am and your temperature is usually 97.6., but today you didn’t awake until 8:30, your temperature will likely read 97.9. Does that make sense?
How do the charts look?
Below are two sample charts: in the first, the woman is not pregnant, and in the second, the woman is pregnant. What you will see is a definite pattern. In the first phase of the cycle, temperatures are generally lower. At ovulation time, the temperatures rise, and they should stay elevated until your period starts. A normal rise is at least .4 degrees, but sometimes the temperatures will spike up almost a whole degree.
What do these changes mean?
In the first phase or follicular phase (from your period until just before ovulation) the temperatures are lower because both your estrogen and progesterone levels are low as the follicles develop in your ovaries. In the post-ovulatory or luteal phase the temperatures increase from the progesterone that is released after ovulation. The temperatures should remain high until your period starts. If you are pregnant, the temperatures will rise up even higher, as shown in the second chart.
How to use this information
So as you can see, once the information is graphed on a chart, the timing of ovulation becomes clear. One important note to remember is that the follicular phase (the first phase) can vary in length dramatically at times. However, the postovulatory phase or luteal phase is solidly stable and varies only slightly between 12-16 days. That means that from the day you get the positive ovulation predictor strip, you should expect your period within 16 days at the very most.
I highly recommend the book, Taking Charge of Your Fertility by Toni Weschler for all of the wonderful information she has compiled and researched so that women can become familiar with their bodies. Personally, I think this should be required reading for ALL women. She goes into great detail about charting the BBT in addition to many other subjects related to female hormones and fertility.
Taking Charge of Your Fertility also has an app for those of you who prefer to chart your BBT that way. You can find all their info at www.tcoyf.com
If you want to learn more things you can do to enhance your fertility, then download my free e-book here: Top Tips for Enhancing Your Fertility (That Fertility Doctors Don’t Want You To Know).
Your Whole Body Wellness Expert
Founder and President of Exponential Wellness
phone: (919) 753.1523
Exponential Wellness provides whole body care with acupuncture, Chinese herbal medicine, nutrition, lifestyle, and dietary counseling. Our mission is to transform women’s lives by restoring vibrant health so that you can THRIVE. We’ve helped hundreds of patients restore their health and vitality.
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