All About The Amnio

Why the risks are not as high as you think

- Merlyn Glass

WHAT IS IT?

Amniocentesis is a prenatal test where a sample of the amniotic fluid surrounding the baby is withdrawn. It’s mostly used for testing of genetic conditions, but can also be used to check if a baby’s lungs are ready in case you need to have a preterm delivery for any reason.

WHEN AND HOW IS IT DONE FOR GENETIC CONDITIONS?

Amniocentesis is usually done between 16 and 22 weeks of pregnancy. After the abdomen is cleaned with sterile fluid, and using a sonar as a guide, a needle is inserted through the abdominal wall into the uterus, and between 10 to 20ml (less than four teaspoons) of amniotic fluid is drawn up. When done for lung maturity, it is performed in the late third trimester.

HOW DOES IT WORK?

Our bodies are made up of thousands of cells which contain the genetic material. This is made up of 23 pairs of chromosomes which hold the genes responsible for everything about us – not only how we look, but everything about us, including how our bodies function.

We naturally lose skin cells everyday (notice the ring around the bath and basin, or dry skin flaking off) and so does the unborn baby. A sample of the amniotic fluid contains the baby’s cells, and these are extracted and analysed in the laboratory.

WHO DOES THE AMNIOCENTESIS?

A skilled obstetrician, foetal medicine specialist, or an experienced radiologist.

DOES IT HURT? DO I HAVE A LOCAL ANAESTHETIC?

A local anaesthetic is not used, because the amniocentesis is relatively quick.