As someone who personally uses the Fertility Awareness Method, I’m used to having to clear up misunderstandings about FAM and its effectiveness. FAM is not (yet) widely used by women in the US, so this is understandable, I guess.
But, hearing the same blatant falsehoods about FAM over and over again can get old. So I’m here to clear up the air, once and for all! (provided EVERYONE in the world will just read this blog post. Come on, guys…)
Here’s a quote I read recently on a popular fertility forum: “My gynecologist told me that BBTs are unreliable and that I shouldn’t waste my time taking my temperature each morning”.
Yeesh. Well, studies show that a biphasic BBT pattern is a reliable indicator of ovulation, so perhaps we have a misunderstanding here. Tracking your BBT does let you know if and when you ovulated, but it only does so after the fact. So, observing your BBT determines the END of your fertile window. In that sense, BBTs are unreliable in determining the whole fertile window if that’s the ONLY thing you’re tracking. Similarly, tracking your cervical fluid or cervical position alone isn’t an accurate way to pinpoint the fertile window. It’s best to track your BBT along with your cervical fluid each day, with cervix tracking as an optional, added confirmation of your fertile days (yes, it’s optional, but cervix tracking is COOL! Try it for yourself).
If you don’t experience a biphasic BBT pattern during a cycle, it’s possible you a) did not ovulate that cycle, b) your thermometer isn’t accurate enough, or c) you aren’t taking your temperature correctly. To make sure you are getting the most accurate temperature, it’s recommended that you use a basal thermometer, which is more sensitive to changes in lower, basal temperatures than a regular thermometer is. Also, you should take your temperature at or as close as possible to the same time each morning, after at least three hours of sleep, and as soon as you wake up – before getting out of bed or doing anything else!
(Want a highly accurate thermometer that's fast, comfortable in your mouth, and doesn't beep? Try Wink, a bluetooth basal thermometer that automatically syncs your temperatures and the time your temperature was taken to the Kindara app).