Definition

An unexpected loss of pregnancy before the 20th week of pregnancy. Most spontaneous abortions happen very early in pregnancy, often before a person even knows they are pregnant. Signs include vaginal spotting or bleeding, pain or cramping in the abdomen or lower back, and the passing of fluid or tissue from the vagina. Spontaneous abortions often occur because of genetic problems in the fetus. Maternal factors or conditions that could contribute to having a spontaneous abortion include problems with the uterus or cervix, infection, hormone problems, severe malnutrition, smoking, drinking alcohol, taking certain medicines, or exposure to radiation. Being older or having certain diseases, such as polycystic ovary syndrome, uncontrolled diabetes, congenital heart disease, thyroid or kidney disease, and immune system disorders, may also put a person at higher risk of having a spontaneous abortion. Also called miscarriage.