How long after starting birth control will it affect your period?

Answer 1

If you are taking one of the pills that stops monthly bleeding it should be effective the first month, if you started taking it the first week of your period. Otherwise BCP react differently in different women.

Some women will stop having a heavy flow the first month, others it may take several cycles to make a noticeable difference. Some women will stop having any monthly bleeding - from using 21 day packets.

Many women have "break through" bleeding off and on for the first two or three cycles - this is any irregular, light bleeding that may last several days or may come and go. (It is perfectly normal as your body adjusts) If this lasts more than three cycles or is heavier than your normal period, talk to your doctor or family planning clinic.