Using the cervical mucus method to promote fertility doesn't pose any risks.
Likewise, using the cervical mucus method for birth control doesn't pose any direct risks, but it doesn't offer protection from sexually transmitted infections. In addition, the risk of unintended pregnancy with the cervical mucus method is somewhat higher than with other methods of birth control.
As many as 23 out of 100 women practicing the cervical mucus method for birth control will get pregnant in the first year of typical use. But, with correct use, the pregnancy rate may be as low as 3 out of 100 women a year using the cervical mucus method for birth control.
Formal training is usually required to master the cervical mucus method. This method also necessitates ongoing, rigorous daily monitoring. In addition, abstinence — or use of another type of contraception — is typically needed for 10 to 17 days of each cycle.