PATHOLOGY

Detailed explanation-1: -Immunoglobulin G (IgG), although it has a high molecular weight, is the only class of immunoglobulins able to cross the placenta and to reach the fetal circulation.

Detailed explanation-2: -IgG1 and IgG3 are transferred more efficiently across the placenta than IgG2. Furthermore, the transfer of antibodies against viral proteins and antitoxins of the IgG1 subclass occurs more readily.

Detailed explanation-3: -IgG is the only antibody class that significantly crosses the human placenta.

Detailed explanation-4: -Introduction. Maternal immunoglobulin G (IgG) is transported across the placenta by an active, neonatal Fc receptor (FcRn) mediated process during pregnancy. This transport can confer short-term passive immunity1, 2, 3 and protect infants against infections during their first months of life.

Detailed explanation-5: -immunoglobulins-IgA and IgM are excluded from crossing the placenta. Thus IgM antibodies in the newborn indicate a response to intrauterine infection.