Spontaneous complete miscarriage is when a non-viable pregnancy is lost with variable amounts of bleeding and pain; women often describe this as similar to a very heavy and painful period. At the end of the process, the uterus is empty and bleeding gradually stops. Diagnosis is usually made by settling of symptoms, but some women choose to confirm with an ultrasound scan.
Spontaneous incomplete miscarriage is when the spontaneous process of expulsion of a non-viable pregnancy starts with pain and bleeding, but remains incomplete with continuing bleeding and lower abdominal cramps. This may require surgical management to get control over the bleeding.
Missed miscarriage is when the pregnancy has stopped growing in the early weeks, but there is no bleeding or only spotting. It is also known variably as a blighted ovum or an anembryonic pregnancy. Often, the woman is unaware that the pregnancy is not developing; sometimes she may notice regression of pregnancy symptoms. Diagnosis of missed miscarriage is by ultrasound scan.