Basal Body Temperature When Pregnant: Does It Drop During Early Pregnancy?

You might know of some mommy friends around you who were able to tell if they were pregnant or not way before they even used the pregnancy test kit – how is that possible? There is a way to find out, and it’s none other than through charting one’s own basal body temperature (BBT). What does it mean to chart your own BBT and how is it a sign of pregnancy? How does a chart look like and for how long will you see yourself having a high temperature? It’s the crash course on charting BBT during pregnancy that you’ve been looking for! Let’s get started.

How does basal body temperature change when pregnant

basal body temperature

A person’s basal body temperature is the temperature at which the body is at immediately upon waking up from a night’s rest. If you want to be extremely precise when measuring your body temperature, the moment you open your eyes, reach out and grab your thermometer – but don’t move the rest of your body! Stay in the same position in your bed and use a thermometer to measure your temperature orally (this is one of the more accurate and convenient ways).

Females have a BBT that changes according to the phase of the menstrual period they are in. The difference between the lowest body temperatures and the highest body temperatures recorded could be anything in the range between 0.3 to 0.5 degrees. From the start of your period to few days before or after the day of ovulation, you’ll see a low body temperature. However, your body temperature will rise and stay in a high range after ovulation occurs.

If pregnancy is established, your BBT won’t drop even when it’s way past the date when your period was supposed to come. If you check your temperature consistently and find that it is in a high range for more than two weeks, you could very well be pregnant.

Pregnant BBT chart

BBT chart

In Week 3 of pregnancy, the fertilized egg implants itself into the endometrium (lining) of your uterus, but the pregnancy test kit won’t be able to pick any sign of this up yet. If you want to play detective and beat the pregnancy test kit by finding out first, you have to be on the lookout for the changes in your body temperature and the other early signs of pregnancy.

A basal body temperature chart looks like the one above. The first day of pregnancy is taken to be Week 0 Day 0. For the first two weeks known as the follicular phase, you’ll have a low basal body temperature. After ovulation occurs, you enter the luteal phase, a two-week period of high basal body temperature.

If you see a high BBT for more than two weeks, the possibility that you’re pregnant is high. To ascertain if your pregnant or not, be on the lookout for other signs like implantation bleeding, abdominal pains, or morning sickness. It’s important that you take into consideration all the signs when trying to confirm your suspicions.

How does the BBT chart look like during early pregnancy?

woman question

Even during the period of having a high BBT, you might see your temperature drop suddenly. This is called the implantation dip, also known as a luteal phase dip. There is no scientific evidence to explain why an implantation dip takes place, and there are many moms who don’t see this on their BBT charts. Just note that it is but one of the many early signs of pregnancy.

When can I use a pregnancy test kit? 

woman pregnancy test kit

A pregnancy test kit can be used a week after the first day your menstrual period was supposed to start. If you have a high temperature for more than 2 weeks, your period doesn’t come and your temperature continues to stay in a high range for about a week more, the odds are in your favor – you might be pregnant!

You might be itching to run down to the drugstore right now to get a pregnancy test kit, but try not to be overly anxious and jump the gun. It might still be a little too early to use a pregnancy test kit as the test kit can’t detect the low levels of hCG in your body yet.

If you want to find out as soon as possible, there are test kits that can test for levels of hCG in between 6.3 miU/ml to 10miU/ml, and so can give you results 5-6 days sooner than the normal pregnancy test kits. Normal pregnancy test kits are able to test for hCG levels of 20 or 25mIU/ml, and so will not give you accurate results just yet.

Basal body temperature when pregnant: Possibility of miscarriage?

woman hospital doctor

Even if one sees their body temperature stay in the high range and are actually pregnant, the possibility of an early miscarriage exists. About 15% of all pregnancy losses take place during this period of high basal body temperature. When a pregnancy loss occurs, the hormonal levels return to normalcy and this causes body temperature to return to normal levels. The female hormone progesterone that causes body temperature to rise is secreted in smaller amounts, and this signals the end of the high BBT period.

However, a missed miscarriage or a missed abortion can happen. This refers to a pregnancy loss that is not recognized by the body, and although the embryo is dead, the body is still preparing itself for pregnancy. Thus, body temperature doesn’t drop and a high BBT will continue to be recorded.

Having a high BTT for a long period of time is a sign of pregnancy, but this alone doesn’t tell you if all is well with the pregnancy, so use the pregnancy test kit and go to a practitioner’s to check that everything is fine.This is because there is a risk of an ectopic pregnancy occurring, and you need both the kit and a proper checkup to confirm that you aren’t at risk).

Continue to measure BBT after confirming pregnancy

 pregnant woman basal body temperature thermometer

Even when you’re done confirming your pregnancy, continuing to record your basal body temperature is a way of keeping watch on your physical condition. Body temperature gives an indication on both baby’s and your health, and will be one telling sign should any anomalies arise. Don’t forget that recording BBT can help you during your pregnancy journey, so don’t cut yourself any slack. Remember that your baby needs you to watch out for them too!