The uterine contractility index: a research and diagnostic tool in dysmenorrhea

Women who experienced severe primary dysmenorrhea had 90 to 120 minutes of continuous uterine pressure monitoring during their peak period of discomfort. During the initial screening cycle, they were given 40 mg of piroxicam, a nonsteroidal anti-inflammatory drug which inhibits prostaglandin synthesis. The pressure tracings were analyzed by a newly proposed ratio, the contractility index. During the painful period, the contractility index averaged approximately 3. When relief was experienced, the contractility index fell to approximately 1.5. Women who experienced uncertain or slight relief had a contractility index of approximately 2. Relief was experienced by 69% of the women screened. A small double-blind, crossover study was carried out on seven of the women. This revealed different responses to the drug in consecutive cycles and suggests that increased prostaglandins are an expression of an underlying process, not consistent with a primary cause of dysmenorrhea.