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ZIMSEC O Level Combined Science Notes:Contraception:Rhythm/Natural Family Planning

How it works

  • Various techniques are used:
  • Learn to recognise the fertile periods in the menstrual cycle and avoid sex during that period
  • Several techniques are used to identify this fertile period:
    1. The temperature method is when body temperature is used to determine the fertile period
    2. Cervical mucus-recognises changes in the appearance of cervical mucus
    3. Calendar method-records of the menstrual cycle are kept for one year and used to predict the fertile period
    4. Sympto-thermal method-is when the daily temperature plus symptoms of ovulation pain and premenstrual tension recorded


  • Between 60% and 90%


  • Accepted by most religious groups
  • Helpful when one is ready to fall pregnant
  • Both partners participate in the process


  • High failure rate
  • A lot of motivation is needed to take and record signs daily
  • Unreliable for women with irregular periods
  • Requires training for one to learn the method
  • Imposes restrictions on sexual activity

To access more topics go to the Combined Science Notes page