Question

ABO hemolytic disease of the newborn refers to incompatibilities that occur due to an OO mother's immune response against AO or BO fetus she carries. Her immune system starts producing anti-A or anti-B antibodies from the beginning of the first pregnancy and most AO or BO fetuses are naturally aborted. For this reason, the observed frequency of AO blood type offspring in OO female x AO (or BO) male matings in human populations is lower than the expected frequency of 50%.

a. True
b. False

Answer 1

The claim that ABO hemolytic disease of the newborn with an OO mother leads to frequent abortion of AO or BO fetuses is false. ABO incompatibility rarely results in severe hemolytic disease, whereas Rh incompatibility can have serious consequences in subsequent pregnancies.

Step-by-step explanation:

The statement regarding ABO hemolytic disease of the newborn being a cause of frequent natural abortion of AO or BO fetuses by an OO mother producing anti-A or anti-B antibodies is false. While it's true that mothers with type O blood have naturally occurring anti-A and anti-B antibodies, they do not typically cause the severe form of hemolytic disease of the newborn that is seen with Rh incompatibilities. Rh incompatibility, on the other hand, can lead to serious consequences. It occurs when an Rh-negative mother becomes sensitized to Rh-positive fetal red blood cells. In subsequent pregnancies with an Rh-positive child, the IgG antibodies produced by the mother can cross the placenta and attack the fetal red blood cells, leading to hemolytic disease of the newborn (HDN), which can be a serious condition leading to anemia and, in severe cases, fetal death. However, it is typically associated with Rh incompatibilities, not ABO.