How to Use Basal Body Temperature Tracking to Get Pregnant

You have most likely heard of basal body temperature (BBT) tracking but you may still be wondering what it is and how to do it. Whether you’re looking to get pregnant naturally or want to use it as birth control, BBT, when done right, can be very effective.

I liked using BBT to conceive with PCOS since my cycle can be irregular and unpredictable. BBT helped me understand my natural rhythms and how my cycle was affected by other things such as diet, lifestyle and stress.

What is Basal Body Temperature Tracking?

BBT is tracking your basal body temperature at rest. Basal body temperature will increase slightly (typically less than ½ a degree F) when ovulation occurs so by tracking your temperature every day, you begin to see a pattern of when your temperature rises and can better predict when to have sex at your most fertile time.

Illustrated in the chart above, your temperature starts out low in the beginning of your cycle (follicular phase), has a small dip right before ovulation and then spikes and is elevated the rest of your cycle (luteal phase) until you have a period. If you are pregnant your temperature will remain elevated due to an increase in progesterone.

I’ve tried BBT, but it doesn’t work for me.

The key to making BBT work is consistency and accuracy. You must take your temperature around the same time each morning, before you get out of bed. Research suggests that you should do it before you talk, sit up, move or get ready for the day. I have my thermometer on my bedside table so the minute my alarm goes off, I can reach over and grab my thermometer without moving or sitting up.

It’s also necessary to get the right thermometer, specifically one that measures to a tenth of a degree. Since you’re measuring your basal body temperature which only changes up to ½ a degree at the most, a normal thermometer won’t pick up on this small change.

I like the Natural Cycles thermometer because it was specifically created for BBT and it pairs with their app that makes it super easy to track your cycle. If you’re a visual learner like me, they have easy to read graphs and charts that show you your most fertile window.

Other Things to Know about BBT

If you’re sick, hungover, slept less than normal or had disrupted sleep, your basal body temperature can be altered, and it can impact the accuracy of tracking with BBT. 

The Mayo Clinic also suggests the basal body temperature method can be used to detect pregnancy. Following ovulation, a rise in basal body temperature that lasts for 18 or more days may be an early indicator of pregnancy.

More questions on BBT or your fertility, jump on Instagram @PCOSPregnancy and leave me a comment or DM.