Pressure-velocity analysis of uterine muscle during spontaneous dysmenorrheic contractions in vivo.

Three-dimensional pressure-velocity (slope) topograms may be constructed to evaluate the uterine muscle's ability to contract under varying conditions of pressure load in vivo. This type of analysis indicates that even at intrauterine pressures that greatly exceed perfusion pressure, the uterus is capable of rates of change as high as +/- 120 mm Hg/sec. The topograms of dysmenorrheic women appear similar among women and from month to month. Dramatic differences in the topograms are noted before the development of menstrual pain and after nonsteroidal antiinflammatory drug therapy. This suggests a possible causal relationship to the pain of dysmenorrhea. These topograms may also represent a sensitive measure of physiology and therapeutic effects.