There are two methods of birth controlling, natural and artificial. Birth control pill is an artificial method.
Why use this? Birth control pills are used to birth control and under advice of a doctor you can use for some other issues.
How this works?
Birth control pills has estrogen and projesterone. There are combination pills which contain both of these hormones and pills with only projesteron. These pills affect for the normal menstrual cycle and stop pregnancy.
How this be taken?
Take these pills on one exact time of every day. Keep note on a calender to avoid forgetting. If forget use a condom. Start within the first 5 days of after the starting of mensus. Start pills before one and half months for birth control of a woman expecting marriage.