in Body Fluids and Circulation (Cardiovascular System, Circulatory system) by

1 Answer

0 votes


The Rh incompatibility in humans happens when the child in in the mothers womb. It occurs when the mother has Rh-negative blood and the fetus has Rh-positive blood.


The Red Blood cells of the fetus and the mother gets mixed by crossing the placenta.

Hence, when the mother is Rh-negative and the fetus is having Rh-positive blood, the mother’s immune system will recognize the fetus Rh-positive cells as the foreign body and will produce the antibodies against those cells. These antibodies will cross the placental barrier and will phagocytized (Kill) the fetus’s circulating Red Blood Cells.

The infant may become jaundiced, due to breaking of Red Blood Cells and release of bilirubin from it. Some times the level of bilirubin rises so high that it can be dangerous for the infant. But most probably the levels are mild only.

In the first pregnancy the antibodies are not developed, as it takes time for the immune system to recognize the Rh-positive cells of the fetus. Hence, if the first child is Rh-positive it wont show any symptoms of incompatibility unless there is previous history of abortion or miscarriages. But, soon after the first pregnancy every Rh-positive child will be affected by incompatibility.

Signs and Symptoms:

The symptoms of Rh incompatibility is seen by the destruction of the red blood cells. The symptoms can be from mild to severe form, which can cause death of infant.

The newborn infant may show the following symptoms:

  1. Hypotonia - (Low muscular tone) and laziness or lethargy child.
  2. Jaundice - there will be yellowing of the skin


  1. There will be presence of polyhydramnios (increased amniotic fluid).
  2. Coombs Test - It is used to detect the autoimmune hemolytic anemia. Hence, there can be positive Coombs test.
  3. Higher levels of bilirubin can be found in the blood of umbilical cord of the infant.
  4. Anemic infant, paleness of the skin. Low RBC counts in the blood.
  5. Low levels of the Hemoglobin in the blood.


The Rh incompatible child suffering from the jaundice is treated with the phototherapy by the use of bilirubin lights. Also the child can be given sunbath.


  1. Hydrops fetalis - Increase amount of fluid, because of which there can be edema.
  2. Kernicterus - Higher level of bilirubin may damage the brain cells.
  3. Sensory problems like hearing problem, speech, seizures, and mental dysfunctions.

It is also called as the Rh-induced hemolytic disease of the newborn: Erythroblastosis fetalis.

Biology Questions and Answers for Grade 10, Grade 11 and Grade 12 students, Junior and Senior High Schools, Junior Colleges, Undergraduate biology programs and Medical Entrance exams.