A comparative study of the effect of high-intensity transcutaneous nerve stimulation and oral naproxen on intrauterine pressure and menstrual pain in patients with primary dysmenorrhea.

Abstract

Our purpose was to compare the effects of high-intensity transcutaneous electrical nerve stimulation and oral naproxen (500 mg) on intrauterine pressure and menstrual pain. An open, randomized crossover study was performed on 12 women with primary dysmenorrhea. Intrauterine pressure was recorded with a microtransducer catheter, and the pain score was assessed by a visual analog scale. Before treatment all patients displayed signs of uterine hyperactivity as judged by a high resting pressure (7.5 +/- 0.4 kPa), high active pressure (24.0 +/- 0.8 kPa), and a high frequency of pressure cycles (13.3 +/- 0.5 contractions per 0.5 hour). Oral administration of naproxen suppressed (p < 0.01) all uterine activity parameters. Treatment with transcutaneous electrical nerve stimulation induced a prompt onset of pain relief in a strictly segmental manner, but there were no significant changes in uterine activity. The pain score was significantly reduced (p < 0.001) from 30 to 60 minutes after treatment with transcutaneous electrical nerve stimulation and from 19 to 120 minutes after naproxen administration. Treatment with transcutaneous electrical nerve stimulation induced a prompt onset of pain relief without any significant changes in uterine activity. Possible mechanisms for the pain relief, decreased uterine ischemia or decreased activity in the pain transmission system at spinal or supraspinal levels, are discussed.