Basal Body Temperature While TTC & During Pregnancy

BBT, TTC, TWW, DPO… OMG! Trying to conceive is full of acronyms! So let’s deep dive into the BBT meaning: basal body temperature.

When you’re trying to conceive, you want to know right away if you’ve been successful. The basal body temperature method is a popular way to be both in tune with your body and aware of any changes, like ovulation or pregnancy.

Pregnancy tests often don’t work until the day of your missed period, even if they are marked to work earlier on the box. When you really want to know whether you have conceived, there are methods you can use to find out right away, including measuring and tracking your basal body temperature.

Many women are interested in finding natural ways to measure their fertility and detect whether they might be pregnant. Keeping track of basal body temperature (BBT), or taking your temperature when you first wake up in the morning, is a quick and inexpensive way to determine your fertility.

Tracking your BBT is also known as “charting” in fertility circles.

📝 In this article:

What is basal body temperature?

BBT stands for basal body temperature — your body’s resting temperature. It can fluctuate at different points in your cycle, whether you’re ill, ovulating, your period is on the way, or if you’re pregnant. [1]

What should my basal temperature be?

If you have a fairly regular cycle, your basal body temperature will follow a distinct pattern. When it comes to basal body temperature, ovulation is a key date.

During half of your menstrual cycle, your basal body temperature will average between 96°F and 98°F. When ovulation occurs, your BBT will rise.

A raised basal body temperature is generally between 97°F and 99°F.

What’s a regular BBT cycle?

If your cycle is regular, you will begin to see a pattern of low temperatures before ovulation and higher temperatures during ovulation and before your period. If you get your period, your body temperature will go down.

What if I don’t see a pattern in my BBT?

While BBT charting will work for many women, not all women exhibit the temperature rise that comes along with ovulation. This doesn’t mean that anything is wrong with you or that you won’t be able to conceive.

BBT can also be thrown off by illness, stress, shift work, oversleeping, drinking alcohol, changing time zones, some gynecological conditions, and certain medications.

What is the difference between body temperature and basal body temperature?

It’s all about the time that your body temperature is taken. Your basal body temperature is the lowest temperature when your body is at rest, but your body temperature is generally an average of your temperature throughout the day.

How to check basal body temperature

Now for how to take basal body temperature. For this, you’ll need a basal thermometer. A basal thermometer is the most accurate way of measuring your BBT.

It’s ideal to take your basal body temperature first thing in the morning when you wake up when your body is at rest and at its coolest. Then place the basal thermometer under your tongue, take the reading, and keep track of it (in a notebook, your phone, basically anywhere you have a record of it).

Yup, it’s that simple!

Can I take my basal body temperature with a regular thermometer?

Not easily, no. A basal thermometer goes lower than a regular digital thermometer, and it is more precise (showing you your temperature to 1/10th of a degree). They also work more quickly than regular digital thermometers. This will allow you to track tiny changes in your basal body temperature.

Basal thermometers are relatively budget-friendly. They are often located in the family planning aisle of the drugstore or discount store.

Where do you put a basal thermometer?

The pregnancy journey is paved with blood tests and urine test strips, so wondering where you put a basal body thermometer is fair. You can take the reading from under your tongue (phew). No awkward insertion needed.

Which thermometer is best for ovulation?

So basal body temperature thermometers have many advantages over a regular thermometer but which ones outshine each other? There are many options to choose from, some more expensive others, that it’s easy to get overwhelmed.

But here’s the thing: as long as a BBT thermometer is user friendly and accurate, you’re already a step ahead of getting handle on when you’re ovulating. To help get you there, here are our top picks:

Birth Control & Basal Thermometer from Natural Cycles

A tried-and-tested Peanut mama pick, this birth control pick comes with a high accuracy BBT thermometer that can measure temperature up to two decimal places.

The kit’s annual subscription includes daily fertility statuses based entirely on Natural Cycles’ fertility finding algorithm.

This is a great pick if you want to suss your fertility window whether you’re TTC or trying not to.

Digital Basal Body Thermometer by MABIS

If you want a no frills BBT thermometer, this one by MABIS features an easy-to-read display that gets straight to the point.

It’s simple design is nicely low-key and hides that impressive memory recall we mentioned earlier.

Digital Basal Thermometer by Easy@Home

A favorite of TTC communities everywhere — including our own — the Easy@Home basal thermometer works with the Premom app to track your ovulation cycle.

It’s clinical accuracy is on point not to mention it’s waterproof and it’s vibrant backlit blue screen is easy to read in the dark – perfect for early winter mornings.

How to chart your basal body temperature

Charting BBT is a simple process. Every morning before you get out of bed, take your basal body temperature and record it on your chart.

It generally takes a few months to see a predictable pattern in your BBT. Over a few months’ time, you will be able to see when you ovulate and when you may become pregnant.

Tips for successful basal body temperature charting

BBT charting is an inexpensive, low-tech way to monitor your fertility and become pregnant. It can also be a form of birth control, especially for women with religious beliefs that prevent them from using hormonal or barrier contraceptive methods or for women not using contraceptives due to side effects or invasiveness.

The important thing to remember is that you have to stick closely to the rules of the game. If your temperatures are inaccurate because you have already gotten out of bed and walked around or if you have had a sip of coffee, your overall BBT charting is not going to be very effective.

Using basal body temperature charting can be a big help for women who can’t afford or don’t want to use over-the-counter ovulation predictor tests, which can get expensive with repeated use. It’s a great way to learn to understand your body and its reproductive cycles.

Even when you’re not trying to get pregnant, it can be a useful tool in understanding how your body works.

1. Be consistent

To chart your BBT, you need to make sure your numbers are accurate. It’s best to take it before getting out of bed in the morning, at about the same time each day.

If you have to get up frequently in the night, your BBT will generally go back down after you have been in bed for about 2 hours.

2. Monitor cervical mucus

In addition to charting your BBT, it can be helpful to monitor your body’s cervical mucus. Combining BBT with cervical mucus charting is called the “symptothermal” method.

Changes in cervical mucus can show your body’s readiness to become pregnant. If the cervical mucus is clear and slightly thicker than normal, you are likely to be fertile. There are many books and online resources available to help you use the cervical mucus tracking system.

3. Track ovulation pain

While not all women experience this, many women do feel a slight crampy pain at the time of ovulation. This pain could be concentrated on one side of the abdomen.

Make a note of this pain on your chart, especially if it coincides with fertile cervical mucus or a rise in basal body temperature.

4. Times to use caution

BBT charting may not be effective at certain points in your reproductive cycle.

If you recently gave birth or stopped taking hormonal contraceptives, it may take a while for your cycles to even out.

If you’re breastfeeding, your basal body temperature may also be thrown off.

If you’re approaching menopause, your temperatures may also not be consistent.

How effective is basal body temperature charting when TTC?

As with most natural fertility methods, the effectiveness rate of BBT charting is hard to measure. As a method for detecting ovulation, some studies predict that BBT is only about 22% accurate, but you must track regularly. [1]

Can I use basal body temperature to time when’s best to try to conceive?

BBT can detect the day you ovulate. Ideally, you should have sex a few days before or after ovulation, since sperm can live for up to 5 days in the reproductive tract.

In a regular cycle lasting about 28 days, ovulation happens around day 14. The advantage of BBT charting is that you can pinpoint your own ovulation date, regardless of whether it matches up with the typical cycle. This is especially useful if you have short cycles (around 21 days) or long cycles (over 30 days). After a few months, you should be able to see your ovulation date on your chart.

If your cycles are reasonably regular, you should get familiar with making sure to have sex on the correct days to give yourself the best chance of getting pregnant.

How long before period does BBT drop?

Usually, your basal body temperature drops one or two days after your period. But if it doesn’t, you may be seeing some early pregnancy spotting or implantation bleeding instead of your actual period.

This may not always be harmful and can depend on the progesterone levels in your body. If your temperature stays up for more than 18 days, it’s a good idea to take a pregnancy test. You can also call your doctor for guidance.

Does temperature rise in early pregnancy?

Typically, yes, your basal body temperature will increase in early pregnancy, even before you know you’re pregnant! Your basal body temperature will usually rise within a day or two of conceiving, and it’ll steadily rise until roughly when your period is due to start.

It doesn’t rise by much — usually a degree or two, but even as little as 0.2 degrees. But if you’re tracking your BBT while TTC, and you notice it steadily rising beyond the date you’re due to get your period, you could be pregnant.

However, it’s around this time that it’s recommended to take a pregnancy test if you’re TTC ‒ after the two-week wait, which is the most accurate way of telling whether you’re pregnant.

What is normal basal temperature early pregnancy?

Generally speaking, the average early pregnancy temperature range tends to be from 97.6°F to 98.6°F.

Can you tell if you are pregnant by basal body temperature?

Sometimes, yes, although your basal body temperature rises and falls during a typical menstrual cycle as well. When you’re not pregnant, you can expect your BBT to rise from your fertile window to the first day of your period.

But your basal body temperature when pregnant tends to stay high for 18 or more days; that could be an early sign of pregnancy.

Does temperature rise after conception?

It’s not really conception that makes your basal body temperature rise, it’s more implantation and your body preparing to become baby’s home for the next 9 months. But your body temperature can also raise just after your peak fertile days (ovulation) until your period, so it can be hard to tell.

How long does BBT stay high if pregnant?

If you’re pregnant, your basal body temperature tends to rise for about 18 days or more ‒ that’s usually a pretty clear sign that you’re expecting. However, at the end of the first trimester and the start of the second trimester, it’s likely to start to come back down.

No matter which brand takes your fancy, tracking your BBT with a basal thermometer can be helpful for getting as much information as possible about how your body works.

If you’re TTC, it can be more effective to track your temperature alongside other fertility awareness methods, like checking the position of your cervix or tracking your cervical mucus.

If you’re still not sure about how to track your BBT, feel free to ask our Peanut community — we’re having the conversation.