Despite a history of heavy vaginal bleeding with clots, a proportion of women diagnosed with complete miscarriage, using transvaginal sonography (TVS), have an underlying ectopic pregnancy (EP). We evaluated the need for hormonal follow up in women with history and scan findings suggestive of complete miscarriage. One hundred and fifty-two consecutive women with findings suggesting complete miscarriage at presentation based on their history and TVS were presented to the Early Pregnancy Unit. Serum human chorionic gonadotrophin (hCG) levels were taken at presentation and 48 hours. All women were followed up until hCG was <5 u/L or a pregnancy was visualised on TVS either inside or outside the uterus. Overall, 9 (5.9%) of 152 women with an apparent complete miscarriage had an underlying EP. A diagnosis of complete miscarriage based on history and scan findings alone is unreliable. These women should be managed as 'pregnancies of unknown location' with serum hCG follow up.