Anovulatory Cycle

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Synonyms

Anovular cycle; Anovulation; Estrogen breakthrough bleeding; Estrogen withdrawal bleeding

Definition

A menstrual cycle during which no egg (ovum) is released.

Description

In an anovulatory menstrual cycle, a woman does not release an egg (ovum), resulting in an infertile cycle. The subsequent release of the uterine lining is known as anovulatory bleeding, rather than menstruation. This condition may happen for many reasons, all of which are linked to atypical levels of estrogen, luteinizing hormone (LH), or follicle stimulating hormone (FSH).

The first half of a normal menstrual cycle is concentrated around increasing the uterine lining (endometrium) and releasing an egg. FSH enables immature eggs housed in the ovary to develop. As these eggs mature, estrogen is released. The rise in estrogen triggers the pituitary gland to release LH rather than FSH. The LH surge causes the most mature egg to be released from its ovarian follicle. The empty follicle is ...