Slow Temperature Rise: Why it Happens & What it Means
If you use basal body temperature to track ovulation, then you know that your chart isn’t always as easy to interpret as it should be. Sometimes you go to sleep feeling quite certain that you’ll wake up to a temperature spike, but it just doesn’t happen.
If you don’t see a rise when you thought you ovulated, don’t give up hope yet! It’s totally possible that you still ovulated, even when your chart doesn’t look the way you expected it to.
What does it mean if you have a slow temperature rise instead of a sudden rise?
Not all women experience an “ideal” thermal shift. In some women, the temperature shift after ovulation happens slowly over the course of a few days. This can mean that it took a little while for progesterone levels to rise high enough to cause a shift in temperature, or that the body responded slowly to the increase in progesterone levels.
Does a slow rise hurt my chances of getting pregnant?
Not necessarily. Sometimes a slow rise is perfectly normal and doesn’t have any implications for your fertility. There are plenty of examples of women who conceived on cycles where they had a slow rise after ovulation.
If your temperatures are low throughout the entire luteal phase, or if your luteal phase is less than 10 days, these could be possible signs of low progesterone, which could make it harder to conceive. But a slow rise, absent any other symptoms, does not indicate a fertility problem.
With a slow rise, how do you know when you ovulated?
Even with a slow rise, a temperature pattern usually becomes apparent after a few days. It can be helpful to consult with other fertility signs such as cervical mucus and cervical position. Ovulation is most likely to occur on the last day of fertile cervical mucus. But with a slow rise it can sometimes be difficult to pinpoint the exact day of ovulation.
How common is it to have a slow temperature rise after ovulation?
We’re not aware of any studies that specifically investigate the occurrence of slow rise BBT charts, but there was an interesting study that compared the temperature shift to the date of ovulation as confirmed by ultrasound. The study found, somewhat shockingly, that only 13 percent of women have a BBT rise within one day of ovulation. For many of the women in the study, BBT did not rise until more than two days after ovulation.