Pain during menstruation or dysmenorrhea occurs in 50% of menstruating women and about 10% are incapacitated for 1-3 days each month.

Pain during menstruation or dysmenorrhea occurs in 50% of menstruating women and about 10% are incapacitated for 1-3 days each month.

Some degree of discomfort is usually experienced by over half of all girls after menarche i.e. onset of menstruation. It has been estimated to be the greatest cause of lost time from work and school.

Dysmenorrhea occurs in 50% of menstruating women and about 10% are incapacitated for 1-3 days each month.

In the first year after menarche 38% of girls develop dysmenorrheal pain

In the second and third year after menarche - 20% experience pains related to menstruation.

About 80% of women who develop dysmenorrhea do so within three years of menarche.

Over the age of 25 years the cause of dysmenorrhea is usually secondary to other pelvic problems.

“The onset of menstruation, called menarche -- pronounced like anarchy -- tends to be a formative memory, seared into the brain with the blowtorch of high emotion." Wrote Pulitzer Prize-winning science writer Natalie Angier in her book, Woman: An Intimate Geography.