Primary dysmenorrhea is primarily caused by an overproduction of which substance?

Primary dysmenorrhea is primarily caused by the overproduction of prostaglandins. Prostaglandins are hormone-like substances that play a crucial role in the menstrual cycle and are responsible for the contraction of the uterine muscles. During menstruation, elevated levels of prostaglandins lead to increased uterine contractions, which can result in significant pain and cramping.

Increased prostaglandin levels are typically associated with the onset of menstrual pain and are a key factor in the pathophysiology of primary dysmenorrhea, which occurs in the absence of any underlying gynecological conditions. This condition is common in adolescents and young women and is characterized by pain that usually begins shortly before or at the onset of menstruation, often subsiding as the menstrual flow diminishes.

The other substances listed, such as estrogen, progesterone, and oxytocin, play different roles in the menstrual cycle and pregnancy but are not primarily responsible for the pain associated with primary dysmenorrhea. Estrogen and progesterone help regulate the menstrual cycle and maintain the endometrium, while oxytocin is involved in uterine contractions during childbirth and milk ejection during breastfeeding, rather than in the mechanism of menstrual pain.