[Secretory immunoglobulin A (S-IgA) in the amniotic fluid supports the fetal maturity profile].

Amniotic fluid levels of secretory immunoglobulin A(S-IgA) were measured by single radial immunodiffusion according to the method of Mancini using a monospecific antiserum against the human secretory component. 114 amniotic fluid samples were examined. The S-IgA values showed a correlation (r = 0.49) with the phospholipid levels. Additionally, it was observed no correlation between Serum and amniotic fluid S-IgA concentrations estimated as parallel investigations in 20 patients. S-IgA values greater than or equal to 82 mg/l were used to diagnose a sufficient fetal lung maturity. False negative values of S-IgA are possible. In 19 cases of newborns without signs of respiratory distress syndrome amniotic fluid S-IgA estimations were performed up to 32 hours before the delivery. False negative phospholipid levels were estimated in 2 cases, false negative S-IgA levels in 4 cases. The measurement of S-IgA in amniotic fluid will serve as an additional parameter for the estimation of fetal lung maturity.