Final answer:
Birth control pills help decrease dysmenorrhea by regulating the menstrual cycle through hormonal feedback.
Step-by-step explanation:
Birth control pills help decrease dysmenorrhea, or painful menstrual cramps, by working on the hormonal regulation of the menstrual cycle. They provide a constant level of both estrogen and progesterone, which negatively feeds back onto the hypothalamus and pituitary, preventing the release of FSH and LH. Without FSH, the follicles do not mature, and without the LH surge, ovulation does not occur. This helps reduce the severity of dysmenorrhea.