Duration of menstrual cycle

Question

Explain the normal duration of menstrual cycle? How does method of the calendar contraceptive work?

Answer 1

Normal duration of the menstrual cycle is 28 days though it may vary among several women or in different cycles of same woman. In calendar contraceptive method, the date n-14 (n minus 14) is used, where n refers to the number of days of normal menstrual cycle of woman (generally n=28). The safety margin +3 or –3 are the days around n-14 in which the intercourse must be avoided in order to avoid pregnancy. (This method is not exempt from failures. A doctor should always be consulted before relying on any of the contraceptive method.)