Blood flow changes in the uterus induced by treatment with GnRH analogues.

The regulation of ovarian and uterine blood flow are important aspects of reproductive physiology. Rapid and profound alterations in the vasculature of the cycling ovary have been reported and suggestions that blood flow to individual follicles may play an instrumental role in the selection and maturation of the dominant follicle in the primate (Zeleznik etal, 1991). More recent data indicates a functional relationship between blood flow and steroid output within the ovarian follicle and corpus luteum (Damber et ai, 1990). Likewise there are extensive changes in uterine vasculature apparent from histological changes which occur at puberty, in pregnancy, and following the menopause. A common feature of these diverse stages in reproductive life are significant alterations in the circulating oestrogen concentrations. This suggests that the uterine circulation appears to be under the influence of ovarian hormones (Geiss and Andersson, 1970). Leiomyomas (fibroids) are a common pathological change found in the uterus. It is essential to be aware that when a patient is asymptomatic with the presence of fibroids, there is no need for surgery. When the patient is symptomatic and the symptoms thought to be related to the presence of the leiomyoma, then surgery is appropriate. Such surgery is recognized not to be without risk when it is associated with myomectomy and the risk is dependent upon a number of features which are summarized in Table I. If surgery is to be embarked upon it would seem sensible to adopt adjuvant treatment in patients with uterine fibroids that would be beneficial in both reducing the size of the fibroids present as well as useful in preparing the patient for surgery and reducing blood loss during surgery. It is with these issues in mind that the role of gonadotrophin-releasing hormone (GnRH) analogues in patients with uterine fibroids, who require surgery, has been investigated in recent years.