Amniocentesis after normal NT NB

Kritika

Hey,

Is anyone done with amniocentesis after normal NT NB SCAN? I had normal scan at week 12 which was normal.. yesterday I was done with my 19th week ultrasound which indicates short nasal bone which was normal in earlier ultrasound.. doctor suggested me to go for amniocentesis as there might be some issue with trisomy 21.. please advise if anyone faced the same..? And how you guys ended with this...?