A threatened abortion is a type of miscarriage (aka abortion) that happens when there is bleeding with or without cramps or low back pain. With such a presentation of bleeding, 50% proceed to miscarriage of the pregnancy.

Management of these patients involves an examination to assess for cervical dilatation, an ultrasound to assess fetal viability, and bedrest for the mother, though there is no scientifically-proven benefit for the latter. When a threatened abortion occurs, no hormones or medications have been shown to prevent it.