Primary dysmenorrhea (PD) is defined as painful, cramping pain in the lower abdomen during menstruation without any identifiable pelvic pathology. The pain usually begins before or at the onset of menses and follows a cyclic pattern, being most severe on the first day and lasting up to 72 hours. PD is characterized by recurrent, spasmodic lower abdominal pain that may radiate to the back and thighs.
PD commonly affects young women and typically begins within 6 to 24 months after menarche, once ovulatory cycles are established. The worldwide prevalence of dysmenorrhea ranges from 45% to 95% among women of reproductive age, with 2% to 29% reporting severe pain.