title: The rhythm method of contraception.
abstract: The rhythm method (safe period) is the only contraceptive method which is approved and actively promoted by the Roman Catholic Church. It therefore holds and attraction to a large number of followers. This paper reviews the historical development of the method from the initial efforts in the nineteenth century to the work of Ogino and Knaus, and covers the variations which are based on alteration of the basal body temperature and changes in cervical mucus. Although this method should be devoid of side effects, certain risks have been reported due to the possible fertilization of an overripe ovum. There may also be a higher risk of ectopic pregnancy than normal to users of this method and these reports are reviewed. The results of field trials concerning the use effectiveness of the method are also examined.
mesh_terms: D000818:Animals; D001831:Body Temperature; D002582:Cervix Mucus / Q000032:analysis; D004971:Estrus; D005260:Female; D005306:Fertilization; D006801:Humans; D008297:Male; D008598:Menstruation; D012252:Natural Family Planning Methods; D010060:Ovulation; D011247:Pregnancy; D011374:Progesterone / Q000096:biosynthesis; D013997:Time Factors
chemical_list: D011374:Progesterone