What basal body temperature reveals about fertility
How often do you take your temperature?
Some people never take it and others only do so when they’re feeling sick. Yet, many women measure it each morning to determine if they have ovulated. Let’s unpack this a little bit and review a small component of the menstrual cycle.
Why Basal Body Temperature is Important
We know that lutenizing hormone spikes at ovulation and causes the egg to be released from the follicle so it can meet sperm. That same follicle is then transformed into the corpus luteum, which ends up releasing progesterone and estrogen for the next 14 days.
Progesterone is the dominant hormone in your luteal phase, and one of its actions is increasing your basal body temperature. This increase is slight (about 0.4 to 0.8 degrees), but significant. It indicates that progesterone is being produced in your body and ovulation has occurred. A rise in temperature in your luteal phase will typically occur during the entire phase.
During your follicular phase, you do not have a corpus luteum producing progesterone, and won’t experience that rise in temperature.
How to measure your temperature for fertility purposes:
Take your temperature as soon as you wake up (this is known as your basal body temperature)
Take your temperature at the same time every morning
Take your oral temperature
Wait until your thermometer beeps (if it’s digital)
Jot it down on a piece of paper or record it in an app
Take note of any significant events – travel, stress, etc.
While this test will tell you when ovulation happened, it can and should be used in conjunction with cervical fluid and position. Tracking these additional fertility signs will provide you with all the information that you need to determine if you are fertile and ovulating.
What affects your BBT?
Having a fever
Drinking alcohol the night before
Not getting at least 3 hours of sleep
Taking your temperature at a different time (than usual)
Using a heating pad or electric blanket
It might take a couple of cycles to get the hang of your temperature patterns. If you’re not noticing a rise in temperature, then you may want to get your progesterone levels assessed (by your MD or ND)!
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