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Overview of Menstrual Disorders

By

JoAnn V. Pinkerton

, MD, University of Virginia Health System

Medically Reviewed Feb 2021 | Modified Sep 2022
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The hormonal interactions that control menstruation occur in the following sequence:

Hormones produced by other glands, such as the adrenal glands and the thyroid gland, can affect the functioning of the ovaries and menstruation.

Changes During the Menstrual Cycle

Changes During the Menstrual Cycle

The menstrual cycle Menstrual Cycle Menstruation is the shedding of the lining of the uterus (endometrium) accompanied by bleeding. It occurs in approximately monthly cycles throughout a woman's reproductive life, except during... read more is regulated by the complex interaction of hormones: luteinizing hormone, follicle-stimulating hormone, and the female sex hormones estrogen and progesterone.

The menstrual cycle has three phases:

  • Follicular (before release of the egg)

  • Ovulatory (egg release)

  • Luteal (after egg release)

The menstrual cycle begins with menstrual bleeding (menstruation), which marks the first day of the follicular phase.

When the follicular phase begins, levels of estrogen and progesterone are low. As a result, the top layers of the thickened lining of the uterus (endometrium) break down and are shed, and menstrual bleeding occurs. About this time, the follicle-stimulating hormone level increases slightly, stimulating the development of several follicles in the ovaries. Each follicle contains an egg. Later in this phase, as the follicle-stimulating hormone level decreases, only one follicle continues to develop. This follicle produces estrogen. As the follicular phase continues, the increasing levels of estrogen cause the lining of the uterus to thicken.

The ovulatory phase begins with a surge in luteinizing hormone and follicle-stimulating hormone levels. Luteinizing hormone stimulates egg release (ovulation), which usually occurs 32 to 36 hours after the surge begins. The estrogen level peaks during the surge, and the progesterone level starts to increase.

During the luteal phase, luteinizing hormone and follicle-stimulating hormone levels decrease. The ruptured follicle closes after releasing the egg and forms a corpus luteum, which produces progesterone. During most of this phase, the estrogen level is high. Progesterone and estrogen cause the lining of the uterus to thicken more and thus prepare for possible fertilization. If the egg is not fertilized, the corpus luteum degenerates and no longer produces progesterone, the estrogen level decreases, the top layers of the lining break down and are shed, and menstrual bleeding occurs (the start of a new menstrual cycle).

Table

During the reproductive years, vaginal bleeding may be abnormal when menstrual periods are too heavy or too light, last too long, occur too often, or are irregular. Any vaginal bleeding that occurs before puberty or after menopause is considered abnormal until proven otherwise. Most causes of abnormal vaginal bleeding are not serious.

Menstrual disorders include

Some disorders that are related to the reproductive organs but not specifically to the menstrual cycle cause some of the same symptoms as menstrual disorders. These disorders include

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