Ovulation, demystified (PART 2): using Basal Body Temperature to confirm Ovulation
Ovulation nation, where y’at?
Ovulation might be my favorite topic to talk about in women’s health, because it’s a ticket to empowerment and bodily autonomy that so many of us haven’t tapped into yet.
I work with women in their twenties and thirties struggling with sub-fertility and period problems like irregularity or severe pain, and diagnoses like PCOS and Endometriosis, and I find that SO MANY of them have no idea when they ovulate, or if they even ovulate at all - and as you can imagine, that leads to a lot of unnecessary stress and heartache when they begin trying to conceive.
Of course, there are lots of reasons to love ovulating (and knowing when it happens) even if you never want babies - I wrote about that in Part 1 of this blog - so go check it out now if you haven’t!
Do you know how to tell when you are ovulating? If YES - YAY! We LOVE body awareness and the empowerment that comes from it. Maybe you have some sense of how to tell, but you are struggling to conceive and are worried you aren’t hitting your fertile window just right. YAY- this blog is for you!
And if you don’t know how to tell when you are ovulating, I want you to know that it’s not your fault, and there’s nothing wrong with you.
Unfortunately, as young girls and teens we are not taught much about our bodies - we might get a little bit in sex ed about having a period, birth control, and a lot of fear-mongering about avoiding pregnancy at all costs. According to this paradigm, ovulation ONLY matters when you are trying to conceive - and that just isn’t the case.
That leaves us in our twenties and thirties ready to conceive (or thinking about it in the next few years), with almost NO knowledge of how the process actually works. Many of us were even led to believe that we could get pregnant on any day of our cycle, and that’s simply not true. In fact, did you know that EVEN in the “ideal” circumstances for conception - meaning you have intercourse on your MOST FERTILE day (in your 5-6 day fertile window), there is only about a 25% chance of conceiving?
This is why if you are trying to conceive, it’s absolutely crucial that you know how to identify when you are MOST fertile so that you can identify small problems before they are big problems, enjoy the process (instead of making yourself batsh*t crazy), and get additional support if things are taking longer than expected.
Before we dive in, I highly recommend reading Part 1 before proceeding. In that blog post, I give background information on fertility and ovulation including:
Your menstrual cycle, ovulation, and your overall health: why it’s important to understand your fertility whether or not you want a baby right now
Reasons to love tracking your fertility signs, and why it pays to start NOW
Your three physical fertility signs and what they tell you about your ovulation
Where to start with tracking your fertility signs and ovulation
And I promised you more… so
In THIS post, we’ll pick up the conversation where we left off !
moving you from the basics to the more in-depth (but still uncomplicated, I promise!) ways to be sure you are ovulating and when.
Today we are going to cover:
Why it’s important to confirm if and when you ovulated by charting your BBT
How Basal Body temperature (BBT) to confirm if you actually ovulated
How BBT tells you when you ovulated
How to track your BBT using a simple and inexpensive thermometer
My tips for getting accurate readings to identify your fertility patterns
Ready? Here we go!
Confirming your ovulation with BBT: Why it’s important
Many of the women I work with who are trying to conceive say they are using LH strips to tell when they should have sex to conceive. Now, LH strips can be a helpful tool, but they might actually be leading you astray.
This may surprise you, but if you can identify your fertile pattern by tracking your cervical mucus and utilize the concepts we’ll cover more in depth in this post, you don’t really need to spend money on LH strips - or at least, you won’t need to use them every day to figure out when you are ovulating.
Here are three reasons OPKs might lead you astray if you are tracking your ovulation and trying to conceive:
Ovulation Predictor Kits (OPKs) tell you you are about to ovulate 1-2 days prior to your actual ovulation, but your fertile window is actually the 5-6 days leading up to ovulation. If you are using these to tell you when to time sex for pregnancy, you might be missing several important days you could be attempting to conceive.
OPKs have a very specific threshold for identifying your LH surge, so you may miss it if you are relying solely on the LH strips to tell you you are about to ovulate (yes, even if you are testing 2x per day)
OPKs ONLY tell you when your LH surges. LH is a hormone that increases right before ovulation, and it can be really useful information to have, especially if you are also tracking your cervical mucus. However, it’s possible to have an LH surge and NOT ovulate, for example, if you have PCOS.
In summary, Ovulation predictor kits do just that - they PREDICT. But if you are concerned you are not ovulating, you can find out at home without having to pay for expensive tests at the doctor’s office (that can also lead to unnecessary stress that will most definitely impact your body wanting to reproduce).
So how do you confirm that you ovulated? Through your Basal Body Temperature!
If you remember from Part 1, basal body temperature is your body’s temperature at it’s lowest metabolic rate, and it increases after you ovulate because the follicle that releases the egg from your ovary turns into an organ called the corpus Luteum, which releases progesterone to help prepare the uterine lining for pregnancy.
Basal Body Temperature is so important to track if you are unsure you actually did ovulate, and it can be helpful to look back on your previous cycle’s temperature patterns to identify where in your cycle you ovulated, especially if you think you are missing your window for conception. Keep reading to learn more!
How your basal body temperature can tell you if you actually ovulated
All that progesterone that’s being released from the corpus luteum after you ovulate is heat-producing, so it causes a slight increase in your body temperature (by about .2-.5 degrees fahrenheit) throughout the rest of your cycle until you get your period. If conception occurs, progesterone levels will continue to stay elevated.
If you are looking back on a previous month’s temperatures, you should see a pattern of lower temperatures, followed by a quick upward shift that stays high through the rest of your cycle, indicating ovulation has occurred and progesterone is surging in your body as it prepares the uterus for a potential pregnancy. See below for an example.
How BBT can tell you WHEN you ovulated
Your basal body temperature will rise 1-2 days after ovulation occurs as progesterone is released into the body in increasing amounts. This should coincide with the drying-up of your cervical mucus as we discussed in the last post!
Your temps will stay sustained at a higher level (usually about 97.8-98.5) for about 10-14 days until your BBT drops suddenly and your period* comes OR your BBT stays high and you get a positive pregnancy test (I recommend waiting at least a full 14 days to test for pregnancy, but I know it’s hard to wait!).
*As a side note, this is also another way BBT can be a great tool if you are not trying to conceive but hoping to get a better handle on your cycles for your overall health and/or to prepare for conception in the future - even though my body gives me lots of signs my period is coming, I know for sure my period will start that day when I see the DROP in temperature after a sustained high. When I had highly irregular cycles, I was still able to tell when my period would start through tracking my ovulation and watching for my BBT to drop.
Remember, if you want to conceive, you also need to pay attention to your cervical mucus changes, because like LH strips, these are your predictors of ovulation, and BBT confirms that you did indeed ovulate.
How to track your Basal Body Temperature
There are tons of options for thermometers and BBT tracking devices these days!
Fancy thermometers that connect to apps on your phone, the Oura Ring, the Daysy thermometer, and even the newer Apple Watch models. But a good ole’ fashioned thermometer will do the trick.
To start tracking your BBT, first, You’ll need to purchase a basal body temperature thermometer, which sounds fancy, but it’s actually not. It is preferred to use a thermometer that goes to two-hundredths of a degree, since for some people, the shift in temperature is more subtle.
These days there are tons of options for tracking your BBT, including fancy thermometers that connect to apps on your phone, the Oura Ring, the Daysy thermometer, and even the newer Apple Watch models. These can all be pretty pricey, but I know many people who like the ease of use and the additional features.
But you definitely don’t have to fork over the big bucks to learn about your own BBT patterns - You can get a really simple, inexpensive one and manually enter the data into an app on your phone or a paper chart, if that’s your thing.
This one from Amazon is only 9 bucks, although I personally prefer this version that has backlighting for $15
Next, start tracking! Keep your thermometer on your bedside table, because you’ll want to take your temperature first thing in the morning, right when you wake up, before you get up, even just to use the bathroom.
Remember, Basal Body Temperature is meant to reflect your body in it’s lowest metabolic state, so taking your temperature before you move around is important to get an accurate reading and start to identify your own fertile patterns.
Pro tip: if you tend to snooze, you can take your temperature, wait for the thermometer to beep, and then later when you actually get up, you can find the reading by using the memory function, and then record the temperature and the time you took it in an app like Kindara or OvaGraph.
Now, this next part is the hard part - actually REMEMBERING to take it.
You may want to set your alarm with a name like “TEMP!” to remind you, but I promise you will soon get in the habit.
IF you miss a day, don’t fret - at the beginning, we are just gathering information about your body’s patterns. You can always take your temperature later and mark in your app that you took it later (so that way if it looks wonky on your overall chart, you can see that it was taken at a later time), but often times it will still follow that pattern of being higher or lower, depending on where you are in your cycle.
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My Tips for tracking Basal Body Temperature:
When you first start tracking your BBT, see it as information gathering, and don’t over-analyze things like when your temperature shift actually happened, or if you had the temperature shift yet. Just take your temperature and log it in your app or chart. Patterns will become clear with time.
Get in the habit of taking your temperature at the same time every day. This can be difficult if you sleep later on weekends, but my recommendation? Don’t worry about it too much. Just mark on your chart that you took the temperature later, so if you see anything that doesn’t fit the pattern, you’ll know that’s why.
Also make note in your chart of anything else that could skew your temperature - traveling, illness, alcohol intake the night before, you took your temp later than normal or after you already got out of bed, your air conditioning went out (or you just slept hot). If you see something that doesn’t fit your pattern (eg, a spike in temperature on day 7 of your cycle), ask yourself if one of these occurred, and simply make mental note of it
DON’T STRESS!! It takes time to get in the habit of charting your temperatures, and it can also take a while to identify patterns in your cycle. If you are just getting off of the pill, you may notice no pattern for a while, and that’s pretty common. If at any point, you feel that tracking your Basal Body temperature is causing you MORE stress than it is empowering you to understand your body, please stop and reach out for help.
There you go - that’s how to track your basal body temperature. Of course, I recommend using this in combination with tracking your cervical mucus, as cervical mucus helps to predict ovulation, and BBT simply confirms. If you are trying to conceive, if you wait until you see a temperature rise, you have missed your fertile window.
I hope this simplifies things for you as you track your ovulation for health, after getting off the birth control pill, to identify patterns for better periods, or to get pregnant if and when you are ready. But I know from working with tons of women like you that this can feel overwhelming as you try to figure things out on your own. If you’re struggling, don’t hesitate to reach out on instagram or fill out a contact form.
If you are trying to conceive and it’s been a while without a positive pregnancy test, I can help! I’d love to work with you to interpret your findings as you track your cycles AND customize a conception strategy specifically for you. Sign up for a free introductory call with me today!
Want to learn more about how to get to know your body, optimize your fertility, and live joyfully all the way from preconception to postpartum? Join my Juicy News email list where we get juicy about all things fertility, pelvic floor health, and new motherhood.
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HI! I’m Dr. Jackie Roelofs, Pelvic floor physical therapist and certified hormone health coach.
I help women like you know, understand, and trust their bodies everywhere on the spectrum of preconception to postpartum, so they can nurture their families, careers, and a life they love while also deeply nourishing and nurturing themselves.
