A 17-year-old girl complains of severe spasmodic lower abdominal pain beginning hours before each period and lasting the first 2 days, occurring only with ovulatory cycles. Pelvic examination and ultrasound are normal. Excess production of which mediator in the secretory endometrium is responsible?

• A Relaxin
• B Progesterone
• C Prostaglandin F2 alpha ✓
• D Vascular endothelial growth factor

Explanation

Primary dysmenorrhea results from exaggerated release of prostaglandin F2 alpha and E2 by the progesterone-primed secretory endometrium at menstruation; PGF2 alpha is a potent myometrial stimulant and vasoconstrictor, producing cramping uterine ischaemic pain. This explains why NSAIDs, which block cyclooxygenase, are first-line therapy and why pain appears only after ovulatory cycles are established. Progesterone falls before menses and does not itself generate the pain.

Reference: DC Dutta's Textbook of Gynecology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.