|MadSci Network: Medicine|
By "woman hood" I assume that you are referring to pain during menstruation, so I'll try to explain why some women experience menstrual cramps. During menstruation, the uterus expels the endometrial lining that has been building up since ovulation in preparation for the arrival of a fertilized egg. If a fertilized egg arrives, then the uterus is nicely set to nourish the developing embryo. If the egg is not fertilized, then the whole lining is shed through the cervix and vagina - this is called menstruation, or menstrual flow, or the menstrual period. The uterus usually contracts during menstruation; the contractions help to expel the uterine lining (endometrium). Menstrual cramps are extremely mild compared to the contractions experienced during labor, and often are not even noticed by the woman. Some of the hormones that regulate the uterine contractions are called prostaglandins, and unfortunately, prostaglandins are often associated with pain. If there is too much of certain prostaglandins, the uterine contractions can be very strong and prolonged, and the woman will experience menstrual cramps. Also, a woman can experience pain during menstruation if some of the prostaglandins "leak" from the uterus and affect other organs such as the intestines. Most women experience some menstrual cramping when they first get their periods, then the pain tends to lessen as the menstrual cycle becomes more regular. Severe, debilitating pain during menstruation may be an indication of endometriosis or another disorder, but for the most part menstrual cramps can be relieved by relaxing, taking warm baths, and moderate exercise (which releases endorphins, the body's natural pain-killers). Allison J. Gong Mad Scientist References: Our Bodies, Ourselves for the New Century: a Book by and for Women. Simon & Schuster, 1998. Carlson, K. J.; Eisenstat, S. A.; Ziporyn, T. 1996. The Harvard Guide to Women's Health. Harvard University Press Reference Library.
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