RESUMEN
INTRODUCTION: It has been estimated that one out of every four women experience first-trimester miscarriage. Missed miscarriage is a common form of early miscarriage where the products of conception are not expelled from the uterus. It is diagnosed by ultrasound. The primary objective of this study was to evaluate the success rate of a combination treatment with mifepristone and misoprostol for missed miscarriage in clinical practice. The secondary objective was to identify significant factors influencing the rate of success. MATERIAL AND METHODS: A cohort of 941 consecutive women with an ICD-10 diagnosis of missed miscarriage who received treatment with 800 µg vaginal misoprostol and 2 repeat doses of 400 µg oral misoprostol after mifepristone pretreatment between 1 January 2012 and 31 December 2014 was analyzed. Women with a uterine size smaller than 12 weeks who were planned for medical treatment were included in the study. The exclusion criteria were primary surgical management or planned follow up outside the Stockholm County Council area. RESULTS: The success rate of medical treatment, defined as no need for surgical treatment, was 85.5% (805/941) in women with a uterine size of less than 12 weeks. However, for women with uterine size below 9 weeks the success rate was 88.9% (586/659). Indeed, uterine size of 9 gestational weeks or larger at time of treatment was identified as the only significant risk factor for surgical intervention. CONCLUSIONS: The medical regimen for missed miscarriage offered in this study appears to be safe and with high rates of success. Conclusions about which women to exclude from medical treatment could not be made. Medical treatment may therefore benefit all women with missed miscarriage who wish to avoid primary surgery.