Spontaneous abortion

**Definition:** Spontaneous abortion (also referred to as miscarriage) is a spontaneous loss of pregnancy (i.e. embryo or fetus) before 22 completed weeks of gestation. When information on gestational age is unavailable, use birthweight less than 500 grams as the criteria. Spontaneous abortions (miscarriages) are distinct from cases of induced abortion.

**Long definition:** Spontaneous pregnancy loss at 22 or more completed weeks of gestation should be coded as a stillbirth.