A 23-year-old nulligravid woman presents to your office with worsening cyclic pelvic pain for the past four years. The pain occurs a few days prior to the onset of menses and continues for five to seven days after menses commences. She describes the pain as constant, cramping, worse on the right and unrelenting. She has associated nausea and low back pain. Occasionally she can get partial relief with non-steroidal anti-inflammatory drugs, but these have become less effective over time. She is sexually active but has most recently been unable to tolerate intercourse due to deep pain. She has never used any form of hormonal contraception. She has no past medical or surgical history. She takes ibuprofen as needed and is allergic to penicillin (rash).