Which Antibodies Cross the Placenta and Protect the Fetus

Question

Which antibodies cross the placenta and protect the fetus?
A)IgA
B)IgG
C)IgM
D)IgD

Accepted Answer

IgG antibodies are the only antibodies that can cross the placenta from the mother to the fetus, providing passive immunity and protecting the fetus against certain infections. IgA antibodies are found in breast milk and help protect newborns from infections, but they do not cross the placenta. IgM and IgD antibodies are not typically found in significant amounts in the bloodstream and do not provide significant passive immunity.