Q: How long should I chart my BBT before seeing a doctor?
A: If your cycles are irregular, you shouldn’t waste time on BBTs alone and you should see a doctor and find out what may be causing the irregularity.
If you do have normal-length cycles and decide to start charting, you only need to wait about 3 months to establish a problem and seek help. For example, if you have a 28-day cycle, but ovulate on day 18, and that happens 2-3 months in a row, you should see your doctor. Otherwise it depends on your age and urgency. It’s not a bad idea for everyone to get preconception advice and bloodwork. At the very minimum this would consist of tests for immunities to rubella, chicken pox, fifth disease, as well as anemia and thyroid function.