39. What is the normal
duration of the menstrual
cycle? How does the calendar
contraceptive method work?

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The normal duration ofthe
cycle is 28 days it can vary among
women or in different of
the same woman.

the calendar contraceptive method
date n-14 (n minus ) is taken
considering nthe of days of the
menstrual cycle of the
(generally n=28). The safety +3
or –3 refers the days around n-14
intercourse should be avoided
prevent pregnancy. (This method
exempt from failures. A must
always be consulted relying on
any contraceptive .)