Second trimester amniotic fluid acetylcholinesterase quantitation in the prenatal diagnosis of neural tube defects.
Amniotic fluid acetylcholinesterase (AChe) activity was assayed in second trimester amniotic fluids by inhibition of non-specific cholinesterase using lysivane. Of the 196 samples analysed, 146 were from normal pregnancies; 11 (5.6%) from severe open neural tube defects; two from small open spina bifidas; seven from fetal chromosome abnormalities and two from severe skeletal dysplasias. In addition nine amniotic fluids were meconium stained and 19 (9.7%) had varying degrees of blood staining. Acetylcholinesterase values remained relatively constant from 13-21 weeks gestation in normal pregnancies and a cut-off limit of 3.2 U/l was set (mean + 2 SD). Heavily blood stained amniotic fluids were associated with AChe levels on or above the normal cut-off limit. Meconium staining caused a non-significant elevation of AChe. No significant elevation of AChe was demonstrated for fetal chromosome abnormalities, or severe skeletal dysplasias. Anencephaly and severe open spina bifida had significantly elevated AChe levels.
D000110:Acetylcholinesterase / Q000032:analysis*; D000653:Amniotic Fluid / Q000201:enzymology*; D004796:Clinical Enzyme Tests; D005260:Female; D006801:Humans; D009436:Neural Tube Defects / Q000175:diagnosis*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis / Q000379:methods*
D000110:Acetylcholinesterase