So I decided to play around a bit with the theme of the blog…hopefully you like it.
This post will be a continuation of my last, FAM: fact or fiction? I left off with a list of three items to monitor for monthly fertility:
1. Basal Temperature
2. Cervical Fluid
3. Cervical Position
I’m going to describe one fertility sign in each of my next three posts, starting with Basal Temperature. I don’t want to leave anything out, so I’d like to devote one post per fertility sign.
Taking your Basal Temperature
Taking your basal temperature is pretty simple. All you need is a basal thermometer and somewhere to record your daily temperature. You can find blank charts online or use one of the apps that currently exist (though, in my opinion, the apps and websites are all pretty awful). As for the basal thermometer, you can buy one at most drug stores. I bought mine at CVS for under $10; it was a bit hard to find, but I finally got hold of one in the “family planning” (aka condom) section. My thermometer actually came with a few blank charts, but I’m currently using the blank tear-out charts in the back of Toni Weschler’s book.
Why my waking temperature?
Your body’s temperature fluctuates throughout the day and is the most consistent while you are asleep. Your basal temperature is defined as your body’s waking temperature and must be taken around the same time every morning, as soon as you wake up. This piece of information is very important, because as soon as you sit up, talk, drink water, or move around your body temperature will start to rise. I’m not saying you can’t necessarily sit up to grab your thermometer off your bed-side table, but I wouldn’t move around any more than absolutely necessary. Your temperature can be taken either orally or vaginally; just make sure to be consistent and do it the same way every morning.
What factors will affect my temperature?
The general rule for basal temp is that you should try to be as consistent as possible with the time you take it every morning. Your temperature will fluctuate only slightly while you are soundly asleep. At least for me, if I sleep more than 8 hours I will generally start to get a bit restless and not sleep as well. So if I take my basal temperature too late in the morning, I find that it is several 1/10th degrees higher than I expected. This may not sound like a lot, but temperatures change quite subtly, though noticeably, throughout your cycle. So if your daily temperature is higher than expected, you may need to discard it.
If you’re one, like me, who usually gets up in the middle of the night for one reason or another, you will want to make sure to take your temperature after you’ve had at least a couple solid hours of uninterrupted sleep. I usually wake up needing to pee at about 3:30 or 4:30 in the morning, so that’s when I’ve started taking my temperature. Since I go to bed around 10 or 10:30 during the week, I’ve already had several hours of good sleep by that point. If I wake up at 1:30 instead, I’ll use the bathroom, go back to sleep and then wait until 5:30 when my alarm goes off to take my temp.
Alcohol will also affect your basal temperature. The rule mentioned in Weschler’s book, and also one that I’ve heard several other places, is that if in the morning you feel like you drank the night before (aka you’re hung over), then your temperature will likely be affected. I usually still take it just to make sure. If it is higher than expected, it may need to be discarded (we will discuss discarding temperatures in its own section below).
The pill and temperature charting:
If you’re like me and have recently come off the hormonal birth control pill (hbcp), your temperatures will probably be a bit crazy for a while. This is because the hbcp suppresses your body’s natural hormone production and replaces the hormones with synthetic “pregnancy” hormones, among lots of other bad things. So it will take at least a few cycles for your body to find it’s natural rhythm. I’ve spoken to women who have gone 6 months without having a period once they come off the pill. I luckily only had to wait a month, but since I regularly check my 3 fertility signs I know that my cycle is nowhere near “normal.” It is important to note that I am not currently using FAM as my primary form of birth control and I do not plan to do so until my cycles (and all 3 fertility signs) have obviously returned to a regular pattern.
On the other hand, if you are au-naturel and have resisted the hbcp poison, first of all , Bravo. Secondly, the stages of your cycle will likely be very predictable after charting only one or two cycles.
So what does a “normal” temperature chart look like?
I’m glad you asked! Below is a chart I found in a simple Google search.
The above chart comes from FertilityFriend, and while many women find this website to be good enough for their charting needs, I have found it to be quite outdated and buggy and instead prefer to chart on paper.
First of all, day 1 of every cycle is the first day of menstrual bleeding (the first day of your period). Not every woman will have a textbook 28-day cycle. They can vary vastly, and for some women will be up to 40 days. The idea that a woman ovulates on the 14th day of her cycle is a complete myth, so remove that information from your head immediately and keep reading to determine your ovulation using SCIENCE! What? Science? Crazy!
The horizontal red line shown through the middle of the chart is called the “coverline.” As you can see, roughly the first half of the data (temperature) points are on or below the coverline, while the second half of the data points are above the coverline. The jump between days 14 and 15 where the temperature makes an obvious shift from below the coverline to above the coverline indicates that ovulation has occurred within the last 24 hours.
If you are charting to become pregnant, this temperature shift is the time when you want to have unprotected intercourse. However, if you are charting to avoid pregnancy, you are not safe to have unprotected intercourse until the evening of the 3rd consecutive day that the temperature is above the coverline. If your temperature dips below the coverline on the 2nd day after the shift, you must start the count over. If you have become pregnant, your temperatures will remain above the coverline and not dip back down as seen in the chart above.
The portion of the cycle where the temperatures are below the coverline is known as the “follicular phase” (the egg is still maturing); the portion of the cycle where temperatures are above the coverline is known as the “luteal phase” (ovulation has already occurred).
Temperatures may fall outside of their normal range for a number of reasons, as discussed previously in this post. If you are just coming off the hbcp and you can’t tell whether the temperature is “normal,” I would personally not discard it and simply make a note of any factors that may have caused it to be high (drinking, early waking, etc). I would only recommend keeping a possibly faulty temperature reading if you are NOT using FAM as your primary form of birth control.
If you have had normal cycles for quite a while and you notice a temperature that seems off, follow the “rule of thumb”: instead of drawing a line between the previous data point and the erratic data point, wait until you have once again charted a “normal” temperature, and draw a dotted line between your two most recent normal temperatures (discarding your abnormal temperature data). Essentially, pretend the erratic data point does not exist. If you’re confused, re-read the instructions while looking at the chart below.
Notice the temperature on cycle day 9 is missing (this is because it was higher than expected), so a dotted line is drawn between the temperatures recorded on days 8 and 10, leaving out the temperature from day 9. This chart also clearly shows the temperature shift (in this case between days 13 and 14) that occurs right after ovulation. Every woman’s cycle is different, so in your case the temperature shift will likely occur on different cycle days. Your cycle may also be longer or shorter.
If this woman is charting to avoid pregnancy, she would be safe to have unprotected sex the evening of cycle day 16 (the evening of the 3rd consecutive day that her temperatures have been above the coverline).
Drawing a Coverline:
For this explanation, we will continue to use the chart shown above. This woman’s temperature jump occurred between days 13 and 14. To draw the coverline, look back at the 6 temperatures recorded before the shift (in this case, days 8-13). Draw the coverline 1/10th of a degree higher than the highest of these 6 temperatures (in this case, temp data for cycle day 8 is missing, so we will ignore that). In other words, between cycle days 8 and 13, this woman’s highest temperature was 97.8 F and occurred on day 12. The coverline will be drawn 1/10th of a degree above this, at 97.9 F.
So I think that’s about all there is to temperature charting. It’s a lot of information, but it’s actually quite easy in practice. Just to recap:
1. Your basal temperature is your waking temperature
2. The temperature shift that occurs (approximately) mid-cycle tells you that ovulation has just occurred.
3. The coverline is drawn using the temperature data from the 6 cycle days prior to the ovulatory temperature shift. It is drawn 1/10th of a degree above the highest temperature that occurred in those 6 days.
4. If you are charting to avoid pregnancy, you are safe to have unprotected sex the evening of the 3rd consecutive day your temperature is above the coverline. If your temperature dips below the coverline before the evening of the 3rd day, you must start the count over.
5. MOST IMPORTANTLY: Every woman’s cycle is different. Your cycle may be 28 days, or it may be 40 days. The idea that ovulation occurs 14 days into your cycle is a MYTH. Use the signs your own body gives you…it’s smarter than you think!