How correctly to calculate days when the woman cannot become pregnant? That schit...

[Igor]

How correctly to calculate days when the woman cannot become pregnant? What to consider or count as the beginning of a menstrual cycle? In what days the greatest probability, what the woman can become pregnant?

[Irtuganov N.S.]

Depends on duration of a cycle. 1 j day of a menses. 15 10 days prior to an expected next menses.