Calendar Method

The Calendar method is the process of tracking dates of a woman’s menstrual cycle to predict ovulation and peak fertility times based on past cycles. The calendar method may be used to decrease or increase the odds of pregnancy. Due to the natural variation of every woman’s individual cycle, using calendar method alone may not be an effective method of birth control or fertility planning.

The calendar method may also be called standard days method (SDM), rhythm method, or natural family planning.