[The determination of acetylcholinesterase activity in amniotic fluid as a further possibility for the prenatal diagnosis of open neural tube defects].

A method for the determination of the activity of acetylcholinesterase (AChE) in amniotic fluid is developed. In connection with other AChE-determination methods for blood quinidine sulphate in a concentration of 2.10(-5) mol/l is used as an inhibitor for the serum-cholinesterase (ChE). With amniotic fluid samples of 162 gravidities are established preliminary limits of reference ranges. The hitherto existing experiences showed that values below the 90. percentile can be classified as normally, above the 99. percentile as pathological findings. This method is to consider among the ultrasonographical examination and the measurement of alpha-fetoprotein in serum and amniotic fluid as a further diagnosis confirming part on the suspicion of the presence of open neural tube defects.