Conception: The Facts

The menstrual cycle begins with the first day of bleeding. This is counted as day 1. The cycle ends just before the next menstrual cycle. The average cycle length is 28 days, but in reality, the usual range is 25 to 36 days. Usually, cycle lengths and the intervals between periods are longest in the years immediately after the first menstrual period and before menopause. Menstruation is the shedding of the endometrium or lining of the uterus along with bleeding. Following ovulation, if the egg is not fertilized it disintegrates and is absorbed into the uterine lining. Since no conception has occurred, the endometrium, unfertilized egg and blood are shed and pass through the vagina. Menstrual bleeding can last 3 to 7 days, with an average of 5 days, for most women.