Amniocentesis – an invasive test

Everyone experiences the procedure differently. Some women report that they feel it with one pregnancy and not with another. If an anaesthetic is used, you may only feel a sharp, stinging sensation for a few seconds, and a sharp pain as the needle enters the amniotic sac. Some women just report a feeling of ‘pressure’ in the abdomen, others report that it was ‘no more than having a blood sample taken’.

What risks and disadvantages are associated with the test?

Amniocentesis, while certainly being the safest of the ‘invasive’ tests, can still lead to a spontaneous miscarriage in 0.5-1% (that’s 1 in 200) of women.

About 1 in 200 women undergoing the test develop an infection or some other complication as a result – this too, can lead to a spontaneous miscarriage. It is possible to have leaking of amniotic fluid – or even a small amount of blood – for a few days after the test, though this stops after a period of bed rest. Some women can develop a high temperature, abdominal tenderness and some uterine contractions, which can also mean that there is infection.

Will I get the results straight away?

Unfortunately, no – as the sample of fluid has to be sent away for laboratory processing and culture. The waiting period can be very long – it can take up to three weeks in fact, for the results, and a diagnosis to be made. Amniocentesis is almost 100% reliable in detecting various abnormalities, but no test is perfect. Occasionally, there can be a failure – when the cells do not grow, for instance – and you may be asked to undergo another one.

If you have undergone the test, and it is found ‘positive’ for some abnormality, you then have to make a decision about a possible termination of pregnancy. At around 20 weeks gestation, it will be necessary for you to have an induced labour and birth.