Variation in some enzymes in amniotic fluid and maternal serum during pregnancy

The following 10 enzymes were assayed in 187 amniotic fluid and maternal serum samples at 15-42 weeks of gestation: alkaline phosphatase, heat-stable alkaline phosphatase (only in amniotic fluid), acid phosphatase, alanine aminotransferase, aspartate aminotransferase, alpha-amylase, gamma-glutamyltransferase, creatine kinase, lactate dehydrogenase, and lysozyme. The normal reference ranges are reported for amniotic fluid and maternal serum enzymes, together with the abnormal values accompanying neural tube defects and EPH-gestosis. The determination of gamma-glutamyltransferase, heat-stable alkaline phosphatase and creatine kinase was found to be of appreciable diagnostic significance in clinical practice.