Placenta abruptio is the separation of the placenta from the uterus
before a baby is delivered, typically in the third trimester of pregnancy but
sometimes earlier. This can lead to preterm birth, low birth weight [at or
below 2500 g (5.5 lb)], and
major maternal blood loss.
Since the placenta delivers oxygen and nutrients from the mother's
bloodstream to the fetus and carries waste products away from the fetus,
placenta abruptio can be life-threatening for a mother (from severe bleeding),
her fetus, or both.
Separation of the placenta from the uterus may be partial or
complete. A partial separation may cause only minor bleeding and not endanger
the lives of the fetus or mother. In rare cases, a complete separation may lead
to fetal death and severe bleeding that can endanger the mother's life.
Symptoms of placenta abruptio can include light or heavy vaginal
bleeding, uterine tenderness or pain, or signs of preterm labor. A pregnant
woman with any of these symptoms must seek emergency medical attention.
Certain factors increase the risk of placenta abruptio, including
high blood pressure, a previous placenta abruptio, smoking or drug use while
pregnant, injury to the abdomen, multiple pregnancy, a blood-clotting disorder,
and a fibroid or scar tissue on the uterus where the placenta grows.