Trial for improved rhythm method.
D019411:Clinical Laboratory Techniques; D003267:Contraception; D003933:Diagnosis; D005193:Family Planning Services; D012252:Natural Family Planning Methods; D010061:Ovulation Detection
Contraception; Contraception Research; Examinations And Diagnoses; Family Planning; Family Planning, Behavioral Methods; Female Contraception; Laboratory Examinations And Diagnoses; Laboratory Procedures; Ovulation Detection; Rhythm Method, Calendar