Ovulation research begins:  WHO assists RP study.
D004544:El Salvador; D005193:Family Planning Services; D007194:India; D007494:Ireland; D012252:Natural Family Planning Methods; D009520:New Zealand; D010061:Ovulation Detection; D010679:Philippines; D014944:World Health Organization
Cervical Mucus Method; El Salvador; Family Planning; Family Planning, Behavioral Methods; India; Ireland; Natural Family Planning; New Zealand; Philippines; Rhythm Method, Calendar; Who