Medical management of miscarriage is an acceptable option available to women, and has advantages of providing timely treatment, while avoiding exposure to surgery and anaesthesia. This retrospective cohort study aimed to determine factors predictive of successful medical management, utilising a single dose protocol of 800 µg vaginal misoprostol. In this cohort, the success rate was 67% (199/296), and smaller mean gestational sac diameter independent of gestational age predicted success (P = 0.046). Success is not significantly related to parity, miscarriage type, pelvic pain or vaginal bleeding at the outset of treatment.