The interval of the menstrual cycle when the female is presumably not ovulating rhythm method.
The time during the menstrual cycle, when conception is not likely to occur, and sexual intercourse can take place, used as a method of contraception.
Time in a woman’s menstrual cycle during which conception is least likely to occur, usually immediately before and after a period and not in midcycle, when ovulation is likely.
The days in each menstrual cycle when conception is least likely. Ovulation generally occurs at the midpoint of an average 28-day cycle, and in women with regular periods it is possible to calculate the days at the beginning and end of the cycle when coitus is unlikely to result in pregnancy.
That period during the menstrual cycle when fertilization of the ovum is unlikely to occur. Ovulation usually occurs about 15 days before the onset of the menstrual period. A woman is commonly believed to be fertile for about 11 days in each menstrual cycle in other words, on the day of ovulation and for five days before and five days after this; this would be the eighth to the 18th day of the usual 28-day menstrual cycle. Outside this fertile period is the safe period: the first week and the last ten days of the menstrual cycle. On the other hand, there is increasing evidence that the safest period is the last few days before menstruation. In the case of irregular menstruation it is not possible to calculate the safe period. In any event, the safety is not absolute.
The time during the menstrual cycle when conception is allegedly not possible. Because of the great variability of the menstrual cycle, it is either extremely difficult or impossible to predict the portion of the cycle in which intercourse may take place with no chance of conception.