n.
or spontaneous abortion
Spontaneous expulsion of an embryo or fetus from the uterus before it can live outside the mother.
More than 60% are caused by an inherited defect in the fetus, which might result in a fatal abnormality. Other causes may include acute infectious disease, especially if it reduces the fetus's oxygen supply; abnormalities of the uterus that have physical or hormonal origins; and death of the fetus from umbilical-cord knotting. The main sign of impending miscarriage is vaginal bleeding.