Hello lybrate-user, thank you for the question.
If the risk in quadruple test is above the cut off for Trisomy21, then I would suggest a confirmatory test for the same. The confirmation can be done either by Amniocentesis
or by Noninvasive prenatal test (NIPt).
Amniocentesis is the USG guided procedure of drawing amniotic fluid which has fetal cells. These fetal cells can be examined for fetal chromosomes. It is a 100% test. The procedure related risk of miscarriage
is very less- about 1 in 500. There is not much pain.
NIPT confirms Down Syndrome up to 99.6%.it is done from mother's blood and hence no risk of procedure related miscarriage.
But I think if your doctor has recommended Amniocentesis, then you should go for it. We Routine ly do it. It's a 10 mins procedure and is important for confirming the Trisomy21.
I hope this is helpful.