Effect of an oral contraceptive on uterine tonicity in women with primary dysmenorrhea.

Hysterometry, a method for quantitative evaluation of the effect of pharmacologically active agents on the myometrium, has been applied to determine the effect of an oral contraceptive on uterine tonicity. Hysterometry was performed on the first day of each of two consecutive menstrual periods in 5 dysmenorrheic women. During the second cycle the women were given ethinylestradiol 50 microgram and lynestrenol 1 mg per day for 22 days. After the intake of this oral contraceptive, uterine tonicity decreased in all women, the decrease being accompanied by relief of dysmenorrheic pain.