Is the amniocentesis a risky thing to do?

Depends,but low risk. Amniocentesis done by an expert is low risk. The main risk is rupture of membranes that often is related to the ultra-structure of the membrane in a given pregnancy. The small risk should be matched with desired benefits; expert counseling can put the risk/benefit in perspective. Seek advice from geneticist and maternal fetal medicine specialist.
Amniocentesis. An amniocentesis with current medical technology carries a low risk of pregnancy loss. With continuous ultrasound guidance during the procedure and an experienced person performing the procedure, the risk of loss is 1 in 1660, based upon a nih study. That's at 16 weeks, though. As pregnancy progresses the risk of loss decreases.