welcome to HealthcareMagic
Aminocentesis is removing a small amount of aminotic fluid from the uterus
of your wife and send it to test.This test is done to look for few birth defect
which a child can suffer like Down's syndrome;Turner's syndrome;trisomy
18 or Edward's syndrome;rare birth and metabolic defects;Rh incompatibility;neural tube defect
etc.These sort of birth defects can occur when a female is pregnant in 35-40 yrs.Whether you have to go in for the test is a question you can discuss with your doctor as she will be the better person to comment as she knows the case better.