This is an example of a healthy cycle for a woman trying to avoid pregnancy. Remember, every woman is different, so you may be perfectly healthy even if your cycle differs from this chart. This woman had unprotected sex during the times that she was not considered fertile. But from the first appearance of cervical mucus and until four days after her peak day and three days after the temperature shift she is considered fertile, so she had protected sex during that time as a way to avoid pregnancy.
What's going on in this chart?
1. Per the First Five Days Rule, this woman is safe to have unprotected sex without risking a pregnancy the first five days of her period (this only applies if ovulation was confirmed with a sustained temperature shift about 12-16 days before. If her cycles have ever been shorter than 25 days in the last year, she would only consider the first 3 days of her cycle safe). Note that even though she is still on her period on day 6, she has protected sex on that day to be safe.
2. Per the Dry Day Rule, this woman is safe to have unprotected sex without risking a pregnancy on any pre-ovulatory day that she observes no cervical mucus. Because she had no cervical mucus on days 7 and 8, she is safe for unprotected sex on those days.
3. As soon as there is ANY cervical mucus, a woman is considered fertile until after she confirms ovulation. This woman had cervical mucus on day 9 of this cycle, so her fertile window started then. She needs to abstain or use protection until she can confirm ovulation with a sustained temperature shift and peak day.
4. The sustained temperature rise along with a return to dry cervical mucus indicates that ovulation has occurred
5. On the evening of the 4th day after the peak day, and the 3rd day after the temperature shift (whichever comes later, to be safe), a woman is considered infertile and safe to have unprotected sex without risking a pregnancy for the rest of her cycle. This woman can have unprotected sex starting on the evening of day 20.