The Beginner’s Guide to Basal Temperatures

Most couples are lucky to conceive quickly. I can’t say how many times I cupped my face in my hands while browsing Facebook, watching couples who hadn’t been together for 6 months — sometimes even 3 months — announce a pregnancy.

The rest of us find it takes a little more work.

Taking basal temperatures serve many functions. They’re 97% accurate in determining whether or not you’re ovulating, which can be useful if you ever find yourself sitting in a reproductive endocrinologist’s office with suspected infertility. Half of the battle is getting that egg out of that darn ovary.

So…how do you take them? How do they tell you if you’re ovulating?

First thing’s first: get a basal temperature thermometer. These bad boys are inexpensive. Mine was only $5 at Meijer. Most of them will include instructions on logging your temperatures.  Temperatures need to be taken right after you wake up, at roughly the same time each day, before you even sit up. If you find that you’re frequently up and down during the night, you’re less likely to get an accurate reading.

Before you ovulate, your temperatures likely range between 97 and 97.7 degrees. A few days after ovulating, you may notice that your temperature rises by about half a degree and stays that way until your next period returns (when your temperatures fall low again, usually a few days before Aunt Flo makes her return).

I used Fertility Friend when I was trying to get pregnant. I’d enter my temperatures every day and let the software do its work. It would usually pinpoint the day I ovulated for me. Since I also used ovulation tests, it was a nice way to confirm that they were lining up with each other. I can do another post on ovulation tests some other time.

The other perk to basal temperatures: they can sometimes tell you that you’re pregnant before pregnancy tests.

After you ovulate, your temperatures will fall and stay low when your period is coming, and it will stay that way until after you ovulate the next cycle. But sometimes, people may see a one-day drop in temperature after they ovulate…and it doesn’t mean Aunt Flo is coming.

It *can* be a sign that an embryo has implanted if your temperature goes back up the next day. It’s exactly what happened to me. I remember sitting with my husband Mike and saying, “My temperature dropped. If it goes back up tomorrow, there’s a 2 in 3 chance that I’m pregnant.”

Burned out by 10 cycles of trying, he simply said, “We’ll see.”

We had been on that road too long already. It was a primary factor in my using about 10 pregnancy tests before I believed “PREGNANT 1 – 2 WEEKS” and the two lines staring back at me.

For your reading pleasure:

Baby Center’s article on basal temperatures