Once a diagnosis of early pregnancy failure has been made, it is normal gynaecological practice to proceed to evacuation of any retained products of conception. In many cases, however, there may be little residual tissue within the uterus, and the patient may be exposed to an unnecessary operative procedure. The purpose of this study was to use sonographically derived measurements of the uterine cavity to select cases suitable for conservative management. Of 50 women presenting with a diagnosis of spontaneous abortion, 32 were chosen for non-operative treatment based upon their uterine cavity measurements. In all of these cases, bleeding had ceased within 2 weeks of selection and the pregnancy test had become negative. There were no subsequent complications. In our opinion, sonographic examination of the uterus allows the selection of those cases which can safely be managed conservatively.