All About Basal Body Temperature During Ovulation

When you start your pregnancy journey, an entirely new vocabulary comes into play. Suddenly, websites, baby books, and doctors are talking to you about things like “follicular phases,” “luteinizing hormones,” and “basal body temperature.”

While you might feel a little like you’re back in high school biology class, learning the language of your reproductive cycle can help you start your pregnancy journey on the right foot and create a successful path to conception.

In this guide, we’ll discuss basal body temperature in particular and how knowing what it means and tracking it can help you conceive.

What is basal body temperature?

During our waking hours, we typically expect our body temperature to hover around 98.6 degrees Fahrenheit. It’s a standard that was set way back in the 19th century, and probably what your mother looked for when she was checking you for a fever. But these days, we regard a normal body temperature as ranging between 98.2 to 98.6 degrees Fahrenheit.

Our basal body temperature (BBT), on the other hand, refers to a number below this range. Basically, BBT is the lowest healthy temperature the body can achieve while in a state of rest. It averages between 97 and 97.5 degrees Fahrenheit in women and is most commonly observed during or just after sleep.

When you’re ovulating, your basal temperature spikes. Occurring in the luteal phase of the menstrual cycle, the spike can be as subtle as 1/10th of a degree—between 97.6 and 98.6 degrees Fahrenheit—but that fraction makes all the difference. This heightened BBT temperature is now referred to as your ovulation temperature.

Why does BBT spike during ovulation?

This uptick in temperature is a result of the fluctuation of the hormones that govern your monthly menstrual cycle. Not sure of how your hormones ebb and flow every month?

Essentially, before ovulation, your hormones surge. These hormones include:

• Estrogen – Which becomes the most high-profile hormone in your body, prepping your reproductive system for its next phase (ovulation, aka the release of your egg).
• Luteinizing hormone (LH) – Which assists in the egg’s growth and release.
• Progesterone – Which triggers the egg’s release from the follicle and increases your BBT. Progesterone is also the hormone responsible for the suite of less-than-pleasant symptoms known as PMS ( thanks, progesterone!).

This temperature rise in your BBT and your resulting ovulation temperature doesn’t taper off until menses begins, after which, your BBT will be restored to business as usual.

How can BBT help you determine when you’re ovulating?

If you’re trying to conceive, getting acquainted with your basal body temperature is an effective way to gauge when you’re most fertile and increase the potential for getting pregnant. This is also known as the “temperature method.”

Because a spike in BBT is an indicator of upcoming ovulation, tracking your BBT can help:

• Determine your ovulation window
• Pinpoint your ovulation day

In using the basal body temperature method, you can identify the window when you’re most likely to conceive. Let’s nail down exactly how to use the BBT method to assess this.

How To Take Your Basal Body Temperature

First things first: because a temperature change in BBT can be tiny (down to 1/10 of a degree!), your best bet is to get a basal thermometer, specifically designed to detect BBT.

Next, decide what method you’ll use to log your daily temperatures. There are a host of apps designed to record and visually chart the changes of your cycle (such as Period Tracker, Clue, and Flo), but if you prefer to kick it old school, you can go analog and print a fertility calendar template for easy visualization.

Below are the steps to take for taking your basal body temperature:

1. Choose a Basal Thermometer: To measure your basal body temperature accurately, use a basal thermometer, which is more sensitive than a regular one.
2. Take Your Temperature First Thing in the Morning: Your BBT needs to be taken as soon as you wake up, before you move, talk, or even sit up. Keep the thermometer within easy reach so you can grab it immediately.
3. Measure at the Same Time Each Day: For the most accurate results, try to take your temperature at the same time every morning, even on weekends. A variation of more than 30 minutes can affect the accuracy.
4. Record Your Temperature: Once you’ve taken your temperature, write it down or log it in an app to keep track of your daily readings.
5. Stick to the Same Method: Whether you take your temperature orally, vaginally, or rectally, stick to the same method throughout your cycle to maintain consistency.

How to Track BBT

Tracking your basal body temperature over time will help you identify the pattern of your cycle and pinpoint ovulation. Start by recording your temperature every morning and charting it on a graph or using a fertility tracking app. Over the course of your cycle, you should notice a slight dip followed by a sustained rise in your temperature, which usually indicates that ovulation has occurred. By consistently tracking your BBT, you can use this data to predict your most fertile days and better understand your cycle’s rhythm.

What should you do with this information?

Well, you beautiful fertile goddess, when you’re trying to conceive, you should aim to get intimate with your partner 2-3 days prior to ovulation because sperm can hang around in your reproductive tract for up to 5 days. This means those little swimmers will be ready to fertilize when your egg makes its big entrance.

Common Mistakes to Avoid

When tracking your basal body temperature, consistency and accuracy are key. Small changes in your routine can lead to incorrect readings, making it harder to spot patterns in your cycle. By being aware of these common mistakes, you can avoid errors and ensure your temperature tracking is as reliable as possible.

1. Taking Your Temperature After Moving Around: Even small movements like sitting up or walking to the bathroom can cause a temperature shift. Make sure to take your temperature before doing anything else in the morning.
2. Using Different Thermometers: Stick to the same BBT thermometer throughout your cycle to ensure your readings are consistent. Switching thermometers can lead to inaccurate data.
3. Inconsistent Timing: Taking your temperature at different times each day can skew the results. Aim to take it within the same 30-minute window every morning for reliable data.
4. Not Recording Daily: Missing a day or forgetting to log your temperature can make it harder to detect ovulation patterns. Try to record your temperature every day to maintain an accurate basal body temperature chart.

How does BBT relate to the fertility awareness method of conceiving?

If you’ve been looking into BBT, you may have learned that it’s most often associated with what’s known as FAM, or the fertility awareness method.

FAM is regarded as a modality for family planning or “natural” birth control, where an individual understands where she is in her fertility cycle using three physical indicators:

• Basal body temperature
• Cervical fluid
• Position of the cervix

You’ll have the best chance of conceiving via fertility awareness based methods if you’re plugged into all three of these indicators, so let’s look at what each one has to offer.

#1: Basal Body Temperature

Now that we’ve covered BBT basics, you’re already wise to how fractional fluctuations in basal body temperature reflect your ovulatory rhythms.

Bear in mind, however, that BBT can also be affected by some other factors:

• Activity – The reason why your BBT drifts south during sleep is that your body does not generate as much heat while in a resting state. As soon as you’re up and at ‘em, your metabolic activity begins its incline and BBT will start to climb in a shift known as diurnal variation. This is why the fertility awareness method is most effective if you take your BBT while you’re in bed, as soon as you wake up.
• Stress – You’d be hard-pressed to find a bodily system that is not impacted by chronic (or acute) stress, and that includes your reproductive system. With anxiety, the heightened disbursement of cortisol and adrenaline can lead to an incline in your baseline temperature.
• Drugs and alcohol – Cigarettes, alcohol, and even some antibiotics can all lead to irregularities in BBT.

#2: Cervical Fluid

Another clue to where you are in your monthly cycle is learning to read the substances produced by your cervix. In an average 28-day cycle, healthy vaginal discharge will likely take the following forms on the following days:

• Days 1–8: Sticky, then nonexistent – During your period, your body produces a small amount of sticky cervical mucus. However, whatever mucus is present is difficult to differentiate from your period blood. In the days following your period, you won’t produce any cervical fluid.
• Days 9–11: Creamy and wet – A cloudy and wet lotion-like consistency indicates your body is gearing up to ovulation.
• Days 12–14: Slick and stretchy – A couple of days before ovulation and during ovulation, your cervical mucus will be slick, stretchable, and slippery—a texture that’s often compared to uncooked egg whites.
• Days 15–28: Sticky or nonexistent – Following ovulation, your cervical fluid becomes more sticky and harder for sperm to pass through. It may remain this way until you get your period, or it may disappear altogether until your period begins.

The texture of your cervical mucus speaks to the critical role it plays in your fertility. The slick and stretchy texture of your mucus immediately preceding and during ovulation not only works as a lubricant to lure sperm towards the cervix, but its pH value also helps sperm reach the finish line (i.e. your egg). When pH is acidic, rather than alkaline, the environment of your uterus becomes inhospitable to sperm.

#3: Position Of The Cervix

The final prong of the fertility awareness method is gauging the position of the cervix. Your cervix, like countless other parts of the body, undergoes miraculous changes throughout reproductive and life cycles to accommodate the changes occurring internally.

In terms of indicating fertility, you’ll find two main positions of the cervix, both of which can be understood intuitively:

• Closed – When you’re not in your fertility window, your cervix feels less pliable and sits lower in the vaginal canal. While your egg is under construction—either before or after ovulation—the walls are up (for now) to any potential suitors.
• Open – When you’re ovulating or have just ovulated, the tissue of your cervix is pliant and soft, thanks to cues from escalating estrogen. There will be a small breach (so small, you might not be able to feel it), leaving the door open for a possible pregnancy.

In most women, the cervix sits 3-4 inches high in the vaginal canal (or 5 inches if you have a high cervix). If you use this FAM method, get in the habit of checking your cervix every few days to learn what its fluctuations feel like before, during, and following ovulation.

If you’re not used to getting up close and personal down below, feeling for cervical changes can seem mysterious, or even daunting—but it’s not much different than handling a tampon or menstrual cup. Plus, learning to read your cervix can help you build a stronger connection with yourself and your goddess-like life-creating powers.

And remember: it’s just you! Just be sure to wash your hands and trim your fingernails beforehand.

Get to Know Yourself—and Your Baby—Better, With SneakPeek

Whether you’re on the cusp of your pregnancy journey or just beginning to learn the language of your reproductive cycle, getting familiar with your own fertility and natural cycles will be foundational to your health, as well as the health of your new family.

Once you’ve successfully conceived, you can get to know your newest family member even sooner. The SneakPeek At-Home Early Gender Prediction Test uses DNA to reveal the sex of your baby as early as 6 weeks into your pregnancy. That’s months earlier than a traditional anatomy ultrasound can tell you. And the best part? There are no doctor’s appointments necessary—SneakPeek is the #1 OBGYN-recommended at-home gender test. All it takes is an easy-to-collect DNA sample.

So, as you begin your pregnancy journey, join the 1 million moms who chose SneakPeek, and choose SneakPeek to join you in this new chapter.

Editorial Policy

At SneakPeek, our commitment is to provide accurate, up-to-date, and reliable information to empower our readers. Our content is thoroughly researched, reviewed by medical experts, and fact-checked to ensure its credibility. We prioritize the well-being and education of our readers, and our editorial policy adheres to the highest standards of integrity and accuracy in all our articles.

This post has been reviewed for accuracy by:

Haley Milot

Haley Milot, a highly skilled laboratory professional, currently serves as the Associate Director of Lab Operations at Gateway Genomics, the parent company of SneakPeek. Her extensive experience in laboratory management, spanning over seven years with Gateway Genomics, showcases her expertise in quality assurance, quality control, and the development of laboratory procedures. Haley's background includes pivotal roles in DNA extraction and purification, real-time qPCR, and specimen accessioning, underscoring her comprehensive understanding of laboratory operations and diagnostics. Her adeptness in managing complex laboratory functions and her deep knowledge of medical diagnostics make her a vital contributor to SneakPeek's innovative approach to prenatal testing.

Sources:

1. WebMD. What Is Normal Body Temperature? https://www.webmd.com/first-aid/normal-body-temperature
2. National Center for Biotechnology Information. Physiology, Ovulation And Basal Body Temperature. https://www.ncbi.nlm.nih.gov/books/NBK546686/
3. The Bump. Tool: Fertility Chart. https://www.thebump.com/a/tool-fertility-chart
4. ONiO. 8 Factors That Influence Your Body Temperature. https://www.onio.com/article/factors-that-influence-your-body-temperature.html
5. VeryWell Family. How to Check Your Cervix and Cervical Position. https://www.verywellfamily.com/how-to-check-your-cervix-and-cervical-position-1960299#toc-what-to-look-for
6. VeryWell Family. When And How Often To Have Sex To Get Pregnant. https://www.verywellfamily.com/when-and-how-often-to-have-sex-to-get-pregnant-1960289