Fertility awareness methods involve determining the most fertile days of the menstrual cycle and avoiding unprotected intercourse.[80] Techniques for determining fertility include monitoring basal body temperature, cervical secretions, or the day of the cycle.[80] They have typical first-year failure rates of 24%; perfect use first-year failure rates depend on which method is used and range from 0.4% to 5%.[2] The evidence on which these estimates are based, however, is poor as the majority of people in trials stop their use early.[80] Globally, they are used by about 3.6% of couples.[3] If based on both basal body temperature and another primary sign, the method is referred to as symptothermal.