Loss of the fetus before the 24th week of pregnancy or viability (the ability to survive outside the uterus without artificial support). The medical term is spontaneous abortion. The majority of miscarriages occur in the first 12 weeks of pregnancy, and may be mistaken for a late menstrual period. Miscarriages may occur because of chromosomal abnormalities or developmental defects in the fetus, or because of severe illness, exposure to toxins, or an autoimmune disorder in the mother. Miscarriages later in pregnancy may be caused by genetic disorders, cervical incompetence, a defect in the uterus, or large uterine fibroids. The symptoms are heavy bleeding with cramping. Slight blood loss with severe pain can be a symptom of either a threatened miscarriage or ectopic pregnancy. Miscarriages are classified medically as different types of abortion. In a threatened abortion, the fetus remains alive in the uterus. In an inevitable abortion, the fetus dies and is expelled from the uterus. In a missed abortion, the fetus dies but remains in the uterus. A pelvic examination and ultrasound scanning may be performed to assess the pregnancy. If all of the contents of the uterus are expelled, no further treatment may be necessary. Otherwise, a D and C may be performed. Missed abortion requires a D and C or induction of labour depending on the duration of the pregnancy. Rh-negative women are given anti-D (Rho) immunoglobulin to prevent complications related to Rhesus incompatibility in future pregnancies. (See also abortion.)


Online Medical Dictionary: Your essential reference to over 5000 medical terms.