One of the most well-known of the antenatal tests, Amniocentisis, is routinely offered to women over the age of 35 to establish whether their baby is at risk of having a genetic condition like Down’s Syndrome. It can also pick up musculoskeletal disorders like Spina Bifida, Cystic Fibrosis and Duchenne Muscular Dystrophy.

During the test, a sample of the amniotic fluid – the fluid that surrounds the foetus in the womb – is taken for testing. This is because the fluid contains cells shed from your baby, which can then be tested for a range of different medical conditions.
Usually, this test is carried out when you are around 18 weeks pregnant and you may have to wait another four weeks for the results.

What happens during the Amniocentisis test?
After emptying your bladder, your womb will be scanned, which will show the doctor where would be the safest place to take a sample of amniotic fluid from. A long needle is inserted through your tummy into your womb to withdraw a sample of amniotic fluid. The test takes between 10 – 30 minutes and afterwards you will be advised to rest well for the next 24 hours.

Side Effects
It is likely that you will experience mild cramps or pain in the abdomen, however, there are potentially more far-reaching implications of having the amniocentisis test and these must be considered before you decide to go ahead and have the test.

One such side effect is that the needle could injure you or your foetus. This is unlikely due to the internal guide the ultrasound scan offers your doctor, but there is always a small risk present.

There is a tiny possibility that your blood will be exposed to your foetus’ blood. This could cause problems if you are Rhesus negative and your baby is Rhesus positive. If exposure has been a possibility you will be offered an injection of ‘anti-D’, so that you don’t react to your baby’s red blood cells.

The test could also cause a condition known as club foot in your baby (this is more likely the earlier you have the test in your pregnancy). There is also a small risk of miscarriage, which needs to be weighed up by you before proceeding with the test. At 18 weeks, you may be able to feel your baby start to move, which could make a termination very traumatic if you were going to consider that option.

Of course, all these negative side effects are low and most women have no problem at all but the period of time you may have to spend waiting for your results can make for an anxious few weeks.

If you would like to talk to other mums-to-be about the amniocentisis test, you can do this on the Tests and Checks area of the chat forum.

Last Modified: 21/06/2007