Should I Use Basal Body Temperature to Track My Irregular Cycles?

August 29, 2022 | By: Kacie Shrock, RN, BSN

When trying to conceive, ovulation is one of the most important things to pay attention to because as we know timing is everything! On average, women with a 28 day cycle ovulate around cycle day 14, when a mature egg is released from the ovaries and into the fallopian tubes and ready to be fertilized.

A woman tracking her cycle using BBT

You may quickly learn that timing is not always the case. In fact, many women do not have a typical 28 day cycle which means the majority of us are most likely not ovulating on cycle day 14. Irregularities in the cycle can make it extremely difficult to identify that crucial moment for conception but there are some excellent, inexpensive solutions you can use to pinpoint and confirm your ovulation. 

What is Basal Body Temperature?

Basal Body Temperature (BBT) is your temperature when fully at rest. BBT is most often used for fertility awareness as ovulation and the subsequent release of progesterone causes a slight increase in temperature.

The most fertile days for a woman to conceive is the few days leading up to the rise in BBT. By keeping an eye on your temp and watching for the temperature  shift, this way you can better understand if ovulation has occurred. 

Pro tip: Use a digital thermometer made specifically for BBT tracking as it has an extra decimal for precision!  

Why Use BBT Charting to Track Irregular Cycles

If you suffer from any hormonal imbalances that cause irregular cycles, or polycystic ovary syndrome, BBT charting can help you identify ovulation, even if you don’t know when you’ll get your next period.

How to chart your BBT with a Premom app

In fact, many women with PCOS often have higher levels of LH throughout their cycle, making it more difficult to determine their true LH peak using ovulation tests, which is why it is recommended to track your cycles using both ovulation testing and BBT. 

The most important thing to note about BBT tracking is that your temperature increases after ovulation has occurred, which is why this is a great tool to help confirm ovulation. But, when trying to conceive it is important to time sex before ovulation to ensure the sperm are waiting for the egg to be released. By tracking BBT over time you may start to notice a pattern in your cycles which will help you time sex accordingly by providing a more accurate estimate of when you will ovulate the following cycle. 

There are many things that can impact your body temperature — including illness, sleep patterns, stress, and alcohol (to name a few). Although BBT can be a great tool to help track irregular cycles, it is best to follow the guidelines for BBT tracking and track for a few cycles to really identify any patterns. It is important to make sure your temperature rise is clear and sustained for 3-4 days before confirming that ovulation has passed. 

Advantages of BBT Charting

BBT charting can:

  • Help you determine a pattern of ovulation.
  • Improve timing of sex for conception. 
  • Detect any potential fertility problems.
  • Allow you to develop a record of your cycle to share with your provider. 
  • Can potentially detect early signs of pregnancy.
  • Allow you to confirm that an LH peak has resulted in ovulation.
Charting BBT easily with a Premom app

Let’s Review

Irregular cycles can cause  lots of frustrations when trying to conceive. Timing is everything and an absent period or delayed ovulation can make it difficult to accurately plan sex for conception. Basal body temperature tracking can be beneficial even for someone who has irregular cycles. By identifying a pattern in your temperatures, you may be able to use this method to accurately confirm that ovulation occurred, better predict ovulation by tracking with ovulation tests, and timing intercourse for the next cycle and develop a record to share with your provider. 

If you are having consistent irregular cycles that are shorter than 24 days or longer than 35 days, you should consider following up with your provider to determine a root cause for your irregularities. It will be beneficial to share your BBT tracking with your provider so they can better understand your cycle patterns and if you are truly ovulating or not. 

Got questions about how to track your BBT with an irregular cycle? Hop on over to our Ask An Expert feature where you can submit your question and get a response from a fertility specialist within 1 business day. 

More BBT tips with our Premom expert!
Charting your BBT easily with a Premom app

About Author 

Nurse Kacie is a registered nurse who specializes in fertility and reproductive health. She has always had a passion for women's health and she supports women and couples virtually across the world while on their journey to their dream families!


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