In order to do the natural family planning or rhythm method, you must keep track of your menstrual cycles. A menstrual cycle lasts from the first day of one period to the first day of the next period. The first day of bleeding is considered day 1 of your menstrual cycle. If it is 28 days until the start of your next period, then you have a 28 day cycle. Maintaining a menstrual cycle chart for about 3 to 6 months will give you a better idea of the average length of your cycles.
Most women ovulate in the middle of their cycle, about 11 to 14 days after the start of a period.
Keep in mind, that things like stress, illness, changes in sleep, and hormonal fluctuations can alter menstrual cycles, making ovulation(and periods) occur earlier or later than usual. Therefore, this method has limitations when used as a birth control method. When used as a birth control method, it is about 75% effective.
If you need more information, contact your doctor or clinic. There are also several good online sources that have information about charting your menstrual cycles.
4. June 2012
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