A 20-year-old woman presents with painful menstrual periods and associated abdominal bloating over the last 6 months. The symptoms are most severe on the first day of her period, and she is concerned because it is causing her to miss work. Her menstrual history reveals regular periods every 28 days that last for 5 days. She denies excessive menstrual blood loss, takes no medication, and denies smoking tobacco or using illicit drugs. Which is considered a first-line treatment for this patient's condition?
1) Nonsteroidal anti-inflammatory drugs (NSAIDs)
2) Combined oral contraceptives
3) Progestin-only contraceptives
4) Gonadotropin-releasing hormone (GnRH) agonists