Primary dysmenorrhea: Clinical sciences

Primary dysmenorrhea refers to painful menstruation in the absence of pelvic pathology. It often starts in adolescence, usually within the first 6 to 12 months of menarche. In fact, dysmenorrhea is the most common menstrual-related symptom in young women. The pathophysiology is likely related to the increased release of inflammatory mediators like prostaglandins and leukotrienes during menses.

When assessing a patient who presents with a chief concern suggesting primary dysmenorrhea, start with a focused history. Patients typically report painful menstruation without a history of underlying pelvic pathology. Their pain usually starts 6 to 12 months of menarche, which is when ovulatory cycles are most often achieved. Now, some patients might also experience a range of associated symptoms, such as pain localized in the lower back, pelvis, or upper thighs as well as possible nausea, vomiting, diarrhea, headaches, muscle cramps, and poor sleep. If you see these history findings, you can diagnose primary dysmenorrhea.

Here’s a clinical pearl! Some individuals do not achieve ovulatory cycles until 1 to 3 years after menarche. In these patients, suspect primary dysmenorrhea if pain began during this time frame and if there is no history of symptoms that suggest associated pelvic pathology. Pelvic examination, including pelvic ultrasound, is not needed, but it could be considered if symptoms progress or fail to improve with medical treatments.

Now that you’ve diagnosed primary dysmenorrhea, let’s talk about treatment. First-line treatment involves nonsteroidal anti-inflammatory drugs, or NSAIDs, for pain relief. Common NSAIDs include ibuprofen, naproxen, and celecoxib. These work by inhibiting the enzyme cyclooxygenase, which converts arachidonic acid into prostaglandins, thus decreasing the production of prostaglandins, which cause the muscles and blood vessels of the uterus to contract.

Be sure to tell your patient that NSAIDs should be taken at regularly scheduled intervals and work best when started 1 to 2 days before the onset of menses and then continued through the first 2 to 3 days of menstruation. There isn't a best choice among them, and it’s okay to try a different NSAID if the first one does not achieve the desired effect. Additionally, counsel patients to take NSAIDs with food and water, which can help decrease their gastrointestinal effects. Finally, emphasize the importance of correct dosage and frequency to avoid subtherapeutic treatment.

Alright, if a trial of NSAIDs doesn't seem to work for your patient, meaning their symptoms still persist, you can try hormonal therapies. This includes a combined oral contraceptive pill or OCP, the contraceptive patch, vaginal ring, single-rod progestin implant, intramuscular or subcutaneous depot medroxyprogesterone acetate, and the levonorgestrel-releasing intrauterine system. Hormonal therapies are thought to work by preventing endometrial proliferation, ovulation, or both, which in turn decreases prostaglandin and leukotriene production.

The choice to use one type of hormonal therapy over another is up to your patient. You should counsel them on the risks and benefits of each therapy available so they can make an informed choice about what’s right for them. Additionally, counsel your patients that hormonal therapies have the added benefit of providing contraception. You may also consider the use of the progestin-only pill, norethindrone, which has been shown to be effective in decreasing symptoms of dysmenorrhea when taken continuously. And don’t forget that NSAIDs can be used in conjunction with hormonal therapy as needed.