Awasome How Long On Birth Control Before It Works References. Web however, depending on when in your cycle you start it, the pill may not be effective for seven days. If it’s inserted at any other time of the month,.

If you start a combination birth control pill within the first five days of your period, then you are likely to be protected almost immediately. Web the pill works by stopping the ovaries from releasing an egg each month. It is injected into the muscle or another subcutaneous area.