Immunoglobulin and C3 levels in normal human amniotic fluid

Forty-one amniotic fluid samples were tested by single radial immunodiffusion, using Hyland plates for the demonstration of IgG, IgA, IgD, IgM and C3. All of the immunoglobulins except IgM could be detected throughout gestation. There was a tendency to increase during mid-pregnancy and thereafter to decrease toward term. IgM was detected in only 5 samples (12.2 percent) obtained at term. The literature is reviewed with particular emphasis on IgD, IgM and C3 in amniotic fluid (AU)