You cannot track your period using your body temperature if you’re taking oral contraceptives. Birth control pills change your hormone levels and stop ovulation, and because the basal body temperature method depends on the hormonal changes that happen during ovulation, it won’t work.
How Does the Basal Body Temperature Method Work?
The basal body temperature method allows you to track your ovulation for natural family planning. You record your body temperature daily, preferably right after you wake up. Your temperature may increase slightly during ovulation, usually by less than half a degree. If your temperature remains higher for three days or more, it may indicate that ovulation has taken place.
If you’re interested in becoming pregnant, you can use this method to chart your ovulation, then try to have sex two to three days before ovulating. If you want to prevent pregnancy using this method, you should avoid unprotected sex for three to four days after your rise in body temperature.
Why Doesn’t My Basal Body Temperature Change on Oral Contraceptives?
Oral contraceptives release hormones that stop ovulation. These hormones make your body think that it’s pregnant and disrupt your normal cycle. On the birth control pill, your body will:
- Stop releasing eggs.
- Thicken the cervical mucus to make it more difficult for sperm to reach the egg if it’s present.
- Thin the uterine lining to make implantation more difficult if fertilization occurs.
This prevents pregnancy on several levels. Because your body isn’t ovulating as usual, your body temperature will not change predictably.
How Can I Track My Period on Birth Control?
If you’re taking birth control pills, you can track your period by counting the number of pills left in your package. If you’re not pregnant, you should get your period when you’re taking the placebo pills in the last week of your pack.