Question

During erythroblastosis fetalis, a Rh- mother's anti-Rh antibodies that have crossed the placenta will cause agglutination of the fetus's Rh+ RBCs. However, the reverse problem never happens when a Rh+ mother is pregnant with a Rh- fetus, that is, antibodies produced by the fetus cannot cause agglutination of the mother's Rh+ RBCs. This is true because ______.

A. agglutinins are physically too large to pass across the placenta
B. fetal antibodies are immature and non-functional
C. antibodies that can cause this agglutination are not produced by a fetus
D. the placenta is a barrier that prevents the passage of all antigens

Answer 1

The reverse problem does not happen when a Rh+ mother is pregnant with a Rh- fetus because antibodies produced by the fetus cannot cause agglutination of the mother's Rh+ RBCs. Therefore, the correct answer is C.

Step-by-step explanation:

The reverse problem never happens when a Rh+ mother is pregnant with a Rh- fetus because antibodies produced by the fetus cannot cause agglutination of the mother's Rh+ RBCs.

One reason for this is that IgG antibodies produced by the fetus cannot effectively cross the placenta and enter the mother's bloodstream. IgG antibodies are the only class of antibody that can cross the placenta from mother to fetus.

Therefore, the correct answer is C. antibodies that can cause this agglutination are not produced by a fetus.