Should I do amniocentesis after positive NIPT?

ACMG recommends it. NIPT is a screening test and is not diagnostic, so confirmatory testing by CVS or amniocentesis is recommended after a positive result, with the risks of the procedure explained to you. The reason is not that NIPT is unreliable, but that it analyses placental DNA rather than the baby's own cells. Confined placental mosaicism — where an abnormality is present in the placenta but not the baby — is a recognised cause of false-positive results. A positive NIPT means the chance is increased. Depending on your age and the specific condition, a meaningful proportion of positive results turn out to be unaffected pregnancies. Ask for the positive predictive value for your result. Amniocentesis also tells you the mechanism — whether it is an extra chromosome, a translocation, or mosaicism — which NIPT cannot distinguish and which affects recurrence risk in future pregnancies. If you decide against an invasive procedure, that is a legitimate choice. ACMG recommends that in that case an effort should be made to obtain cord blood at birth so the result can be confirmed then. Ask for this to be arranged in advance rather than remembered on the day. Before deciding, ask for referral to a genetics professional or foetal medicine specialist. You are entitled to accurate, balanced information about the condition, and to time to consider it. A positive screening result is not an emergency.