How does the Ovulation or Billings Method of natural family planning work?
This method relies on the observation of changes in the quality of vaginal mucus around the time of ovulation. One day before, during, and one day after ovulation, the vaginal mucus (arising from the cervix) may change in quality to become opaque, sticky and tacky. The recommendation is to check vaginal secretions before urinating and examine the elasticity, consistency and lubrication. Intercourse can be resumed on the fourth day after peak mucus production. It is less reliable for women who have an insufficient quantity of mucus, or vaginal conditions, for example, vaginal infections, masking cervical mucus changes. The couple is not protected from sexually transmitted diseases including HIV.
