North Shore Hospital Maternity Services (Waitemata DHB)
Downs Syndrome Screening
Screening for Downs Syndrome and other chromasomal (genetic) abnormalities is now routinely offered. Women are advised to undergo some risk screening prior to any diagnostic screening as there are risks associated with invasive screening methods.
Risk screening tests - there are two tests available, one in the first trimester and one in the second trimester. Please see the National Screening Unit website for details www.nsu.govt.nz
Diagnostic tests - these should only be recommended to women with a high risk of chromasomal (genetic) abnormality.
Chorionic villus sampling (CVS) involves taking a small sample of the chorionic villi, which are the tiny units that make up the placenta. Using ultrasound as a guide, the sample is obtained by inserting a cannula up through the vagina and cervix (transcervical) or by inserting a needle in through your stomach (transabdominal).
Amniocentesis involves taking a small sample of amniotic fluid from around the foetus with a needle introduced through the stomach.
Both these tests carry a risk of miscarriage.