What is the safe period to participate in sex to avoid pregnancy and how to calculate?
Contrary to popular belief a woman is only fertile about 5 days (a week at the longest) of her cycle. However unless a woman is actively charting her cycle then she will not know when this fertile time is, and since a woman’s cycle can change without warning, her only clue that her ovulation day has moved may be when she gets a positive pregnancy test. This is why people will say a woman can get pregnant any time in her cycle. A woman will ovulate 12-16 days before her period, because once she’s ovulated the luteal phase (phase between ovulation and menstruation) is only a finite length. Once she has ovulated she WILL menstruate 12-16 days (average is about 14 days) afterwards unless she conceives (in which case she won’t menstruate again for about 9 months). The problem is that the day a woman ovulates can change, so simply looking on a calendar, predicting when she will usually menstruate and guessing that she must ovulate on day 14 of her cycle, doesn’t work. It is possible however
