Objective. The primary aim of the study was to assess the incidence of intracavitary pathology visualized by saline infusion sonohysterography (SIS) in premenopausal women suffering from abnormal uterine bleeding refractory to medical therapy. Secondary aims were to evaluate the clinical course when a minimally invasive therapeutic approach was applied and to examine the need for hysterectomy in this group of women over a follow-up period of two years. Design. Prospective cohort study. Setting. Tertiary referral university hospital. Population. Between February 2004 and June 2006, 104 premenopausal women suffering from abnormal uterine bleeding refractory to medical treatment were included. Methods. Transvaginal ultrasonography and SIS were performed as first line procedures of the investigation. Hysteroscopy was undertaken for removal of focal intrauterine anomalies. Hysterectomy was only carried out when other approaches failed or were regarded as unsuitable. Women who did not undergo hysterectomy had regular follow-up consultations for at least two years. Main outcome measures. Incidence of intrauterine focal anomalies, clinical course, and need for hysterectomy. Results. Following saline infusion sonohysterograhy intracavitary anomalies were visualized in 58 (55.8%) women. Over the follow-up period 80 women had successful minimally invasive treatment, while 24 women underwent hysterectomy. Conclusions. The study shows that focal intracavitary lesions are common in premenopausal women with abnormal uterine bleeding refractory to medical treatment. By applying minimally invasive diagnostic and therapeutic approaches acceptable bleeding patterns can be re-established in most cases, thereby resulting in a low rate of hysterectomies.