ACHE and neural tube defect: Neural tube defects can be evaluated by measuring amniotic fluid alpha-fetoprotein and acetylcholinesterase to assess neural tube defects.[7,8] Moreover, as a widely used prenatal diagnostic method, amniocentesis is relatively low-risk, and a systematic review and meta-analysis showed no significant risk of miscarriage increased by amniocentesis when women undergoing invasive prenatal testing and controls had a similar risk of chromosomal abnormalities.[9] Furthermore, amniocentesis is safer after 14 to 15 weeks of gestation than before 14 to 15 weeks of gestation.