Menstrual Disorders

Menstrual Disorders: Irregular and Missed Menstrual Periods Image

A woman’s body usually prepares for pregnancy about every 28 days. Her cycle begins on the first day of bleeding and continues to the first day of the next menstrual period.

Every woman’s body is unique. For some, a cycle is as short as 21 days or as long as 35 days, and for some women, each cycle is different from the previous. What is irregular for one woman may be normal for another.

If a woman has irregular or abnormal menstrual bleeding, a doctor may prescribe hormones or other therapies (including different birth control methods) to help regulate her period.

How much blood flow is considered normal? Doctors consider about 30 to 80 milliliters (2 tablespoons to about 1/3 cup) normal; anything less or more than that could be considered abnormal menstrual bleeding.

Irregular menstruation and abnormal menstrual bleeding fall into several different categories.

Amenorrhea is the failure to start menstruation during puberty or cessation of menstruation. Some of the normal causes of amenorrhea are pregnancy, lactation and menopause.

Dysmenorrhea is the medical term for menstrual cramps. “Primary dysmenorrhea” is not caused by an underlying medical condition and generally begins when a girl first starts having her period. “Secondary dysmenorrhea” typically occurs later in life and is the result of a problem with the woman’s reproductive system.

Menorrhagia is excessive, dysfunctional uterine bleeding that occurs as a normal part of a woman’s menstrual cycle. Blood flow may be high in volume (over 80 milliliters—about 1/3 cup) and may last longer than a normal period (usually eight to ten days).

Premenstrual Disorders

Premenstrual syndrome, or PMS, is a group of physical and emotional symptoms that occur in the latter half of the menstrual cycle following ovulation. Symptoms, which can include backache, bloating, irritability and headache, are typically most intense during the seven days prior to the start of menses.

Premenstrual dysphoric disorder, or PMDD, is a more severe form of PMS that also includes a psychological component. For a PMDD diagnosis certain symptomatic criteria must be met and the symptoms must interfere with daily living.


Techsol. (nd). Premenstrual Syndrome (PMS). Retrieved August 15, 2002, from

U.S. Public Health Service’s Office on Women’s Health. (2000). Menstruation. National Women’s Health Information Center. Retrieved August 15, 2002, from