Influence of danazol on uterine activity. A pilot study

The influence of danazol treatment on uterine activity was studied by means of repeated intra-uterine pressure recordings in two women with laparoscopically diagnosed endometriosis. During a control cycle the women had normal plasma levels of FSH, LH, estradiol and progesterone and repeated recordings showed a varying uterine activity, with irregular small contractions in the follicular phase and regular ones with maximal amplitude and duration at the onset of menstruation. Treatment with danazol inhibited the fluctuations in circulating gonadotropins and invariably caused low levels of ovarian hormones. Between 2 and 3 weeks after starting treatment there was a period of increased myometrial activity and increased reactivity of the uterus, but thereafter a marked inhibition of the contractions was seen. It is suggested that danazol could be of value in the treatment of painful conditions with excessive uterine activity, such as primary--and to some extent also secondary--dysmenorrhea.