title: Self-observation of the cervix to distinguish days of possible fertility.
authors.forename: E F
authors.initials: EF
authors.lastname: Keefe
mesh_terms: D001695:Biology; D003267:Contraception; D005193:Family Planning Services; D008598:Menstruation; D010061:Ovulation Detection; D012098:Reproduction; D012106:Research
keywords: Biology; Cervical Mucus Method; Clinical Research; Contraception; Family Planning; Family Planning, Behavioral Methods; Fertile Period; Natural Family Planning; Reproduction; Reproductive Period; Research Methodology