Sunday, April 20, 2008

How do birth control pills work?

More than one person has asked me this during my time as a sexual health educator. And since I got the positive response I did to the post on EC, I thought it might be time to offer up a little info on what exactly "regular" birth control pills do.

So, as a person of the female persuasion, your hormones do a little dance every month (guys, this is also true of you, but to a much smaller extent, and not on such a cyclical basis). The big players here are FSH (follicle stimulating hormone), LH (luteinizing hormone), estrogen, and progesterone. At the beginning of the month (day 1 of your period), estrogen levels start to rise as the ovaries get an egg ready for its uterine debut...y'know, getting the manicure, picking out a nice dress, getting the bikini wax. Whatev. Also, you're bleeding and cramping and, if you're like me, generally feeling like ass. When the egg's ready *ding!* estrogen falls off a cliff, FSH and LH spike like crazy, and BAM! An egg is released. Then progesterone, released by both the corpus luteum (the part of the egg setup that doesn't actually go on the magical journey down the fallopian tubes...the basket the egg is held in, if you will) starts to release progesterone, in a sense saying "OK, we've ovulated. All right, nothing to see here, the egg's on it's way; get a move on, people." And then the CL stops secreting progesterone and falls apart and you're back to day one, bleeding and cursing all over again.
The standard pill has estrogen and progesterone in it, and basically fools your ovaries and the rest of your body into thinking you've ovulated already (remember, the corpus luteum as Officer Barbrady from South Park?). Thus, you aren't popping out any eggs; and if there aren't any eggs, there aren't any potential bambinos. Et voila. It also thickens the cervical mucus--fun, eh?--making it harder for the sperm to get around...and, in fact, for the egg (if it manages to sneak out) to get around. Like swimming in corn syrup versus water. Last, it makes it harder for a potential embryo to implant. When you take your 'dummy' pills--the sugar pills that make up the last week of the pack--you suddenly don't have progesterone coming in, and *ta da* you get your period. Or, if you're like a lot of women, you skip that week and go right to your next pack, and don't get your period. Actually, that's perfectly safe to do; there's no 'health' reason to have your period.
It should go without saying, but (duh) taking BC pills doesn't protect you from diseases, and if you don't take it at the same time every day, or if you skip days, it's not as effective and you could end up preggo. So if you get off on your pill-taking schedule, use another back-up form of contraception for the rest of your cycle (like condoms or a diaphragm).
Have fun and stay safe!

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