Amniocentesis

On the day

When you visit Adelaide Women’s Imaging for an amniocentesis you will be greeted by one of our friendly reception staff who will show you to the room where the procedure will take place. You may need to change into a medical gown for your procedure.

The procedure is performed by an Adelaide Women's Imaging obstetrician and gynaecologist.

After the procedure is completed the fluid is sent off for laboratory tests. Once we receive the results one of our qualified obstetricians / gynaecologists will prepare a comprehensive report for your referring GP or specialist.

FAQs

How long does it take to get results?

The laboratory tests take between 10-21 days for chromosome studies (and up to six or even eight weeks for some specific biochemical tests).

What are the risks of an Amniocentesis?

International figures suggest the maximum risk of miscarriage due to the test is around 1:200.

What must I do / not do after the test?

You should avoid exertion for around 24 hours after the procedure. Preferably your partner, friend or relative should accompany you to drive you home. As this is a medical procedure, with the use of sterile equipment etc., children are not admitted to the procedure room. It is advisable to arrange for someone to care for your children during this time, so that you can rest.

The procedure of amniocentesis has been developed to diagnose certain genetic diseases and some serious abnormalities during pregnancy. This involves taking a sample of amniotic fluid, which surrounds the baby. Floating in the amniotic fluid are some of the cells from the baby's skin, which can then be analysed.

The amniocentesis is performed at 14-16 weeks into the pregnancy. Before this date it can be more difficult to obtain fluid, and the fluid may not contain sufficient cells for the laboratory tests to be performed. Delay beyond 16 weeks carries no advantage.

Why is this test performed?

The test can diagnose chromosomal abnormalities in the baby. Down syndrome is the most common of these abnormalities. However, there are other chromosomal abnormalities which may be detected. If this is so, the implications of the abnormality for your baby will be discussed with you. Genetic counselling may be required in some instances.

The test can also be used to diagnose a number of rare hereditary metabolic diseases. However, the laboratory procedures are very specific and are only performed if you are at a high risk of having a baby with this problem, after having been investigated by Clinical Geneticist. Tests of this kind need to be arranged well before the date of the amniocentesis, as special laboratory preparation is often required.

The test does not prove that the baby is normal. In every pregnancy there is a small but definite risk that the baby may have an abnormality. Chromosome abnormalities account for only 5% of these abnormalities. Therefore, a normal result of this test cannot rule out all other problems (e.g. heart defects, cerebral palsy, autism, cystic fibrosis, club foot, autism cleft lip etc.)

Preparation

No special preparation required - maintain normal fluid intake. Do not empty your bladder for 20 minutes prior to the procedure.

Procedure

The procedure is performed in our medical rooms. Admission to hospital is not necessary. The patient lies on her back and a fine needle is passed through the lower abdominal wall into the uterus and amniotic sac. The fluid is then withdrawn with a syringe.

After your Procedure

  • You may have some lower cramping abdominal pain (a little like period pain).
  • You should not expect any bleeding.
  • Take 24 hours off work and arrange for child-care if you have young children.
  • Relax at home. Sometimes bed or lying on the couch is the only way to ensure you do rest.
  • No intercourse for 48 hours.
  • You may shower.
  • Avoid public pools and spas.