Amniocentesis screens for CAH. CAH, known as congenital adrenocortical hyperplasia or congenital adrenocortical hyperplasia, is a group of autosomal recessive disorders caused by a deficiency of the enzyme 21-hydroxylase in the synthesis of adrenocortical steroids.The 21-hydroxylase gene is located on chromosome 6, and a sample of the fetus can be obtained by amniocentesis for genetic testing of the chromosome. If a couple has the gene for congenital adrenocortical hyperplasia, it is recommended that they consult a prenatal genetics clinic before having children. After all, amniocentesis is an invasive procedure, and there is a certain risk of miscarriage with amniocentesis after pregnancy. However, if you need to rule it out after pregnancy, it can be done around 18-22+6 weeks of pregnancy. Congenital adrenocortical hyperplasia may affect the growth and development of the fetus, it is recommended to follow the doctor’s instructions to improve the examination and evaluate the situation.