A 25-year-old woman presents to your clinic with complaints of heavy menstrual bleeding, dysmenorrhea, and acne. She has a history of irregular menstrual cycles and pelvic pain. A pelvic ultrasound reveals multiple endometrial cysts within the uterine wall, suggestive of adenomyosis. You counsel the patient on the benefits of combined oral contraceptive pills. Which of the following is true concerning the effects of combined oral contraceptive pills?
