What is hypothyroidism?
Hypothyroidism is a condition where the thyroid gland is underactive. This means the gland doesn’t produce enough of the thyroid hormone, which can affect the rest of the body. Common causes of hypothyroidism are autoimmune diseases, such as Hashimoto’s thyroiditis, surgical removal of the thyroid, and radiation treatment.
For more information on what hypothyroidism is, the symptoms, and advice on when to see a healthcare professional, head over to our blog post on the subject.
Can I use Natural Cycles if I have hypothyroidism?
Yes, you can use Natural Cycles if you have hypothyroidism and you're not using any kind of hormonal treatment.
There are also no changes to Natural Cycles’ effectiveness if you have hypothyroidism: Natural Cycles is 93% effective with typical use and 98% effective with perfect use. Hypothyroidism can cause fluctuating temperatures. Regularly fluctuating temperatures may cause the app to struggle with detecting your ovulation, and you may receive more Red Days (days when you should use protection – we recommend condoms – or abstain from vaginal intercourse) if it struggles to detect ovulation.
If you are treating your hypothyroidism, your temperature will most likely be a bit colder than the average. However, this won’t stop the app from detecting your ovulation. Keep an eye on the Graph view — the temperature increase after ovulation should still occur, and the algorithm should still be able to find your fertile and non-fertile days.
You may also experience irregular cycles; these cause more Red Days for those using NC° Birth Control since the app has to provide a safety buffer for the shifting ovulation day. The algorithm is designed to minimize risk, so if there’s a chance you may be fertile, you’ll be given a red day. You can still trust the Green Days you get (in the Today view).