anovulatory cycles

:-anovulatory cycles

In anovulatory cycles, the maturation and differentiation of the endometrium caused by progesterone do not occur. Thus, the sequence of events is greatly altered with variable estrogen alone. Excessive stimulation results in a hypertrophic endometrium, which leads to irregularly irregular bleeding (i.e., irregular interval and irregular duration of bleeding). This is usually heavier in amount than normal (ovulatory) menstruation.



The period is qualitatively similar to an ovulatory one, but minimal coiling of the spiral arterioles probably can cause only small fissures and no propagating hematomas. Peeling away of the functionalis layer thus takes place only imperfectly in the proliferative or hyperplastic endometrium. Bleeding from terminal arteriolar loops must occur, but tissue loss is minimal. The endometrium continues to proliferate from month to month, with the result that hemorrhage often ensues in subsequent periods from this grossly thickened tissue. Paucity of estrogen leads to an atrophic endometrium, which may also lead to irregularly irregular bleeding but generally is less frequent and much lighter in the amount of blood lost