How do birth control pills work?

How do birth control pills work? | Go Ask Alice!:

'via Blog this'Finally, birth control pills traditionally come in packs of 21 or 28 pills. Both types of packs contain 21 active pills. The 7 extra pills in the 28-pill pack are placebo pills which are there to remind you to continue taking one pill everyday and to remind you when to begin the next pack. Whether you take placebo pills or simply wait 7 days to start the next pack, the 7-day break from hormones triggers monthly bleeding that mimics a woman's menstrual period. Women are still protected from pregnancy during this time as long as they have taken all the active pills consistently and correctly. For more details, take a look at Why do I menstruate while on birth control? in Go Ask Alice! archive for Sexual Health.


(So drug companies can sell tampons? and pads, of course.)