Calendar Based Methods Of Contraception


Birth control, or contraception, is a method to prevent pregnancy. There are many ways to carry out contraception, one of which is using the calendar based method. However, this is a highly risky method that requires a couple to have thorough knowledge about how it works in order not to accidentally have a baby. This article will help you know more about this method.

What is calendar based contraception?

Calendar based contraceptive methods monitor the fertile periods during the menstrual cycle in order to prevent pregnancy. A woman checks her menstrual cycle’s length in a span of six months to track the routine. Then she tracks the progress through each cycle in the future from the first day of the menstrual bleeding. This method helps the woman know when she is fertile so that she can avoid having sexual intercourse on those days.

This method can be divided into two branches:

  • Standard days

This method can be used by those who want to prevent pregnancy and still have regular menstrual cycles. However, the standard days method should be used with caution, especially by those who have irregular menstrual cycles.

  • Calendar rhythm

Contrary to standard days method, the calendar rhythm method is one in which a woman does some calculation on the fertile and infertile days of her menstrual cycle after comparing them with her own menstrual cycle. This method can be used by women who have irregular menstrual cycles which are usually shorter or longer than normal.

How do these methods work?

Calendar based methods alert women on when to avoid sexual intercourse or opt for alternative contraceptive methods during the fertile days of their menstrual cycle.

The correct use of calendar based contraception

  • Standard days
    • Mark the first day of the menstrual bleeding as the start of the menstrual cycle.
    • Use a calendar to keep track of the menstrual cycle.
    • Avoid unprotected sexual intercourse during day 8-19 of the menstrual cycle or use alternative contraceptive methods on these days.
    • The method is 95% effective between day 1-7 of the menstrual cycle and from day 20 starting of next
  • Calendar rhythm
    • Monitor the length of each menstrual cycle for a period of six month
    • Keep on monitoring the length of each menstrual cycle and utilizes the most recent monitored cycle.
    • A woman should subtract 18 from the number of days of her shortest menstrual cycle in the six month period to calculate the first day of her menstrual cycle. To calculate the time when she stops being fertile, she should subtract 11 from the number of days of her longest menstrual cycle.


  • These methods are not entirely effective as there are some women who have irregular cycles.
  • They prove to be ineffective in protecting against sexually transmitted diseases (STDs). The use of condoms is strongly advised in this case.
  • Constantly keeping an eye on the dates may be troublesome to some women.

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Hello Health Group does not provide medical advice, diagnosis or treatment.

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