THE MENSTRUAL CYCLE 



a Graafian follicle, the discharge of its egg, and the formation 

 of a corpus luteum. This in turn sets up the progestational 

 or "premenstrual" state of the endometrium. When the corpus 

 luteum degenerates, menstruation ensues because of the with- 

 drawal of progesterone. In some cycles, however, especially 

 in young girls and in women approaching the menopause, a 

 follicle does not ripen in the ovary, but after about the same 

 interval as in an ovulatory cycle, namely 4 weeks, some proc- 

 ess not yet understood leads to reduced action of estrogenic 

 hormone, and bleeding ensues which we call anovulatory men- 

 struation. 



This view of the cycle requires, of course, much more in- 

 vestigation before we shall be able to understand the whole 

 process; I have already pointed out the larger gaps in our 

 knowledge. It certainly represents a great advance toward 

 the truth; and what is indeed important, it gives us a far 

 clearer and more hopeful viewpoint about the disorders of 

 menstruation than do older concepts of the cycle. Since men- 

 strual bleeding is caused by fluctuation in levels of the ovarian 

 hormones, it follows that noncyclic, pathological bleeding, 

 such as occurs in excessive and irregular periods may also be 

 caused by abnormalities in amount proportion, or kind of 

 these hormones. We must consider that there are not two 

 sharply distinct kinds of functional bleeding, one being nor- 

 mal menstruation and the other abnormal hemorrhage. On 

 the contrary, the modern hypothesis tells us that we must 

 expect a series of types of hemorrhage ranging from normal 

 menstruation through every grade of disturbance to the most 

 severe disorder of the cycle. Gynecologists are already be- 

 ginning to study and treat these distressing and difficult con- 

 ditions in the light of this concept, and we may well hope 

 these same hormones that control the normal cycle will help 

 us to control its aberrations and at last to banish the specter 

 of uterine hemorrhagic disease. 



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