Disadvantages:
  It takes a lot of motivation. You have to keep a daily record of observations and stick to the rule of no intercourse during your fertile period.
  You need a lot of instruction before you have any idea how to interpret the structure and colour of your cervical mucus (not confusing the mucus with vaginal discharge and semen after you had intercourse).
    It does not protect you against STD’s.

Advantages:
  You don’t need to go to the doctor.
  There are no side effects.
  You can use this method if you want to become pregnant and want to know what days you are most fertile.