Review Question - QID 109073

A 32-year-old woman presents to her primary care provider with pelvic pain. She reports that for the last several years, she has had chronic pain that is worse just before her menstrual period. Over the past 2 months, she has also had worsening pain during intercourse. She denies dysuria, vaginal discharge, or vaginal pruritus. The patient has never been pregnant and previously used a copper intrauterine device (IUD) for contraception, but she had the IUD removed 1 year ago because it worsened her menorrhagia. She has now been using combined oral contraceptive pills (OCPs) for nearly 1 year. The patient reports improvement in her menorrhagia on the OCPs but denies any improvement in her pain. Her medical history is otherwise unremarkable. Her temperature is 98.0°F (36.7°C), blood pressure is 124/73 mmHg, pulse is 68/min, and respirations are 12/min. The patient has pain with lateral displacement of the cervix on pelvic exam. A pelvic ultrasound shows no abnormalities, and a urine pregnancy test is negative. Which of the following is most likely to confirm the diagnosis?