Approximately 15% of registered pregnancies end in spontaneous abortion, and for 50 years or so dilatation and curettage (D&C) has been the usual management. In a prospective randomised trial we compared the clinical results after either expectant management or D&C, for miscarriages of less than 13 weeks' gestation in which transvaginal ultrasound examination showed intrauterine tissue and/or blood clots with a diameter 15-50 mm. 103 patients were randomised to expectant management and spontaneous resolution of pregnancy occurred within 3 days in 81 cases (79%). 52 patients were randomised to D&C. 3 infections were diagnosed among patients who underwent expectant management (3%); 5 infections and 1 case of postoperative anaemia were observed among patients randomised to D&C (11%). The duration of vaginal bleeding was a mean of 1.3 days longer in the expectant management group (p < 0.02). Convalescence time, time during which patients experienced pain, and packed-cell volume 3 and 14 days after inclusion did not differ significantly between the groups. This study shows that expectant management of selected cases of spontaneous abortion has a similar outcome to D&C.