Which Antibody crosses placenta?
Ans. (a) IgG1(Ref: Maternal, Fetal, & Neonatal Physiology: A Clinical Perspective; pg 484)All four IgG subclasses cross, although the IgG1 and IgG3 subclasses are predominate.IgG1 crosses earliest in pregnancy & is the primary immunoglobulin transferred before 28 weeks.IgG3 crosses later & does not reach maternal levels until after 32-33 weeks
IgG1
IgG4
IgA
IgD
Immunity