The cramps are there to help shed the lining of your uterus, actually. Usually you get the cramps within the first couple of days, when the uterine lining is hardest to begin shedding. The cramps will help it pull away from the rest of the uterine wall so that it can be expelled.
So, in essence, cramps are a good thing. It means your body is working properly. If you do NOT expel the lining of your uterus then it can become very thick, making it had to conceive a child in the future and (when you DO have a period) making cramping worse. It's just a normal woman cycle to keeping the body in tip-top shape for pregnancy, whenever that does happen.
You should always allow your body to cramp some though so that everything can be loosened and expelled properly. You don't have to let your body cramp all day for two days straight, of course, but allowing it to do what is necessary is better for you in the long run. If you must use methods to reduce the cramping (after awhile, of course) then you may want to ask another Advicenators question about that.
So, in short, your body cramps during menstruation to help break loose the old lining of your uterus and expel it and this is a very good thing.
DangerNerd answered Wednesday January 28 2009, 10:10 pm: My understanding is that this is the uterine wall breaking the stuff that is about to come out of you loose so it can be expelled. [ DangerNerd's advice column | Ask DangerNerd A Question ]
ohitscassidy answered Wednesday January 28 2009, 5:51 pm: well cramps are when the uterus muscles tighten and then release i was told it was your bodys way of preparing for when the day comes and you give birth there like mini contractions or something like that [ ohitscassidy's advice column | Ask ohitscassidy A Question ]
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