[Value of an assay of enzymatic activity in amniotic fluid for the detection of fetal anomalies].

Gamma-glutamyl transpeptidase (GGT), and alkaline phosphatase (ALP) and its intestinal and placental isomers were measured at between 12 and 32 weeks after the LMP in the amniotic fluid of 492 pregnancies, including 400 used to establish normal values. Three cases of trisomy 21, 2 of trisomy 18 and one case of mucoviscidosis were tested. Amniotic GGT decreased during normal pregnancies while total ALP and the intestinal isoenzyme remained stable. These intestinal enzyme levels were lowered in the presence of chromosomal abnormalities (autosomal trisomy) or mucoviscidosis. Levels of these enzymes were determined in 5 multiple pregnancies which culminated in the birth of normal infants.