What is amniocentesis and when should I do it?

Hi Dr Chong. I'm in Week 12 now and done my NIPT. results showed that my baby has low risk of abnormality. However, her NT is 4.9mm. We are not sure if we should go ahead with Amniocentesis as it was introduced to us by our Gynae...

Amniocentesis is to put a needle into the waterbag under ultrasound guidance to draw out amniotic fluid, which is sent to the laboratory to culture chromosomes to check for chromosomal abnormality. It used to be the gold standard with an accuracy of more than 90%. Unfortunately, this procedure has a miscarriage risk of 1 out of every 200 patients, so it is not usually offered to patients unless for reasons such as - the nuchal translucency is very thick (which means a high chance of fetal abnormality) - the fetal abnormality test shows abnormalities and you want to determine if it is chromosomal abnormality. These days, we have other tests such as NIPT with high accuracy rate. If the NIPT shows abnormality, you would then need to undergo amniocentesis. If you have a strong family history of abnormality, amniocentesis will be offered to you.