High-risk pregnancies and amniotic fluid isoamylase activity.

A kinetic test (Phadebas) was employed to determine the isoamylase activity in 77 amniotic fluid samples taken from a total of 60 high-risk pregnancies at different gestational ages. It was ascertained that in high-risk pregnancies the s-type isoamylase level frequently deviates from the common scatter range of the respective week of gestation. The measured activity of the s-type isoamylase is subsequently set in relation to the pre- and postnatal state of the newborn. The findings support the assumption that in addition to ultrasound, hormone determination and cardiotocography, the estimation of s-type amylase activity in amniotic fluid may serve as an index for fetal well-being. A reduced secretion of the parotid gland as a result of fetal stress is discussed as a possible cause of the ascertained enzymatic changes in the amniotic fluid.