BBT Charting (Basal Body Temperature) Do's and Don’ts

Basal body temperature tracking is a way to both identify when you ovulated and confirm that you have ovulated in the last cycle.

The basis for basal body temperature, or BBT tracking, is identifying the increase in a hormone called progesterone that occurs after successful ovulation. Progesterone actually raises your basal body temperature by 0.5 - 1 degree Fahrenheit after ovulation. When this thermal shift is present, it indicates sufficient progesterone levels to confirm ovulation.

Smart apps like Premom can use this information to help predict when your next month’s ovulation will occur, so you can time intercourse correctly and maximize your chances of getting pregnant. BBT is quite simple once you get the hang of it, but there are some key "do’s and don’ts" that will ensure you have better success with temperature tracking to monitor your health or fertility.

DON'T take your temperature sporadically or only around ovulation.

You don’t usually need to temp during your period; however, you might if your period is on the longer side. Be sure to test your BBT throughout the entirety of your cycle! Because we are looking for a “shift” in temperatures, we need many days worth of data to confidently identify this change.

DO take your BBT (basal body temperature) daily.

That’s right, every single day! The reason being that we look for 6 consecutive low temperature followed by 3 consecutive high temperatures, in order to confirm ovulation. If you aren’t testing every day throughout your cycle, you could miss this key shift. Without it, a “coverline” cannot be added to your chart, separating the low pre-ovulatory temperatures from the higher post-ovulatory temperatures.

DO take your BBT immediately upon waking.

Your basal body temperature is your body’s lowest temperature at rest. When you begin to move, or are out and about, it increases your body temperature and doesn’t let you get an accurate picture of your body temperature when at rest. It’s only in this “resting” state that we can really see the impacts that sex hormones fluctuating can have on your BBT.

DON'T eat or drink before taking your BBT.

Cold water, hot coffee, teeth brushing . . .  even chewing gum can all throw off your BBT! Because we want to get an accurate snapshot, stick that thermometer in your mouth immediately upon waking, morning breath and all!

DO take your temp at the same time every day.

It’s best to set that alarm clock and take your BBT at the same time every day. When you wake up daily at 6am on weekdays but not until 11am on the weekends, it could cause a variance in your temperature readings. It’s best to keep it consistent -- ideally within a half hour -- of when you normally wake up.

DON'T talk or get up before taking your BBT.

Talking can cause a cooling effect and potentially shift your oral temperature reading. Moving, walking (even if it’s just to the bathroom) could begin to alter your body temperature, so it’s best to take that temp before you move a muscle!

DO use a special thermometer meant only for BBT, and DON'T use a regular thermometer for BBT.

Basal body temperature thermometers extend an extra decimal place to give you a more precise temperature reading, and these little changes matter, a standard oral thermometer for when you are sick will simply not do! Premom has a “smart” Bluetooth-enabled thermometer that automatically syncs with your phone, so you don’t have to worry about writing your temperatures down or manually inputting numbers.

DO use in conjunction with the Premom app to synchronize and chart your temperature.

Paper charting leaves too much room for human error and takes a while to get used to! Premom’s smart technology removes the guesswork for you, graphs your temperatures, predicts your ovulation and identifies your coverline.


Try a free Premom app fro your BBT charting & tracking


DON'T focus on any one individual temp, but rather the trend (coverline).

It’s the trend that matters! Our key takeaway is identifying low pre-ovulatory temperatures versus high post-ovulatory temperatures. This is why tracking daily and throughout your entire cycle is essential, as we discussed above.

DO get at least 3 hours of sleep before you take your temperature.

Sorry new moms, you’ll need 3 hours of consecutive sleep before waking to take your BBT. This allows your body to fully rest and get an accurate reading. If breastfeeding with a newborn, or if you work night shifts, take extra caution when using BBT to avoid pregnancy, as you do need this consolidated sleep for accuracy.

DO turn on the BBT reminder in your app.

Premom makes it easier to remember to take your temperature daily!

Basal body temperature tracking has been around for a long time and for good reason! It’s easy and inexpensive, it gives you tons of information about your body, especially when you take advantage of smart technology with a Easy@Home Bluetooth thermometer that syncs directly to the Premom app.

Happy temping!