Question

Which of the following situations will be fatal to the first fetus?
A. Rh-negative male marries Rh-positive woman
B. Rh-positive male marries Rh-negative woman
C. Rh-positive male marries Rh-positive woman
D. Rh-negative male marries Rh-negative woman

Answer 1

Hint: Rh factor is called Rhesus factor. It is a type of protein found on the outside of red blood cells. The protein is genetically inherited. If a person has the protein, that person is Rh-positive. If the person did not inherit the protein, the person is Rh-negative.

Complete answer: Rh incompatibility is a condition that develops when a pregnant woman has Rh-negative blood and the baby in her womb has Rh-positive blood.
1. The baby is Rh-positive when the woman is married to an Rh-positive male.
2. During pregnancy, red blood cells from the unborn baby can cross into the mother's blood through the placenta.
3. If the mother is Rh-negative, her immune system treats Rh-positive fetal cells as if they are a foreign substance.
4. The mother's body makes antibodies against the fetal blood cells. These antibodies may cross back through the placenta into the developing baby. They destroy the baby's circulating red blood cells.

Additional information: Usually, the firstborn infants are often not affected unless the mother had past miscarriages or abortions. This would sensitize her immune system. This is because it takes time for the mother to develop antibodies. All children she has later who are also Rh-positive are also at high risk.

So, the answer is B. Rh-positive male marries Rh-negative woman.

Note: Rh incompatibility develops only when the mother is Rh-negative and the infant is Rh-positive.
Nowadays, the problem has become less common in places that provide good prenatal care. This is because special immunoglobulins called RhoGAM are used during such cases when a mother is seen to have an allergic reaction due to it.