Amniocentesis

Amniocentesis is a prenatal diagnostic procedure used to assess your baby’s health by testing a small sample of amniotic fluid, the fluid surrounding your baby in the womb. During the procedure, a thin needle is carefully inserted through the abdomen into the uterus under ultrasound guidance to collect the fluid sample.

The sample is most commonly analysed to examine the baby’s chromosomes and can help diagnose certain genetic conditions, chromosomal abnormalities, and other conditions affecting the baby.

• Timing: The procedure is usually performed from 16 weeks of pregnancy onwards.

• Location: The procedure takes place at the Fetal Medicine Unit (FMU) at the Women and Child Health (WCH) building.

Do I need to prepare before the procedure?

No special preparation is usually required.

• You do not need to fast and can eat and drink normally.

• You do not need to have a full bladder.

• You do not usually need strict bed rest after the procedure. However, you should take it easy and avoid strenuous activities for the rest of the day.

You can usually resume your normal activities the following day, as advised by your doctor.

What to expect during the procedure

• When you arrive at the FMU, a nurse will assist you and take you to the ultrasound room.

• The doctor will explain the procedure, and you will have the opportunity to ask any questions.

• You will be asked to sign a consent form before the procedure.

• You will need to provide your blood group details. Blood group and antibody screening are important to determine whether you are Rhesus (Rh) negative.

• If you are Rh negative, you may be given an Anti-D injection, as recommended by your doctor, to help protect the pregnancy.

• The doctor will use ultrasound to identify the safest location for collecting the sample.

• Your abdomen will be cleaned with an antiseptic solution and covered with sterile drapes, leaving the procedure area exposed.

• A thin needle will be inserted through your abdomen into the uterus to collect a small sample of amniotic fluid.

• Local anaesthesia may be administered if needed.

Risks and pain management

• Amniocentesis carries a small risk of miscarriage. Your doctor will explain the risk associated with the procedure and your individual circumstances before obtaining your consent.

• There is a very small risk of infection.

• Most patients experience only mild discomfort during the procedure. Local anaesthesia may not always be necessary.

• Paracetamol may be taken after the procedure to relieve discomfort, if appropriate and as advised by your doctor.

When to call your doctor

Most women feel well after the procedure. However, seek immediate medical attention if you experience any of the following:

• Fever or chills.

• Persistent or severe abdominal pain or cramping.

• Vaginal bleeding or leakage of fluid.

• Flu-like symptoms or feeling generally unwell.

Results

• Results are typically available within 1–2 weeks, depending on the tests performed.

• The laboratory will contact you when your report is ready for collection.

• You can schedule an appointment with your primary consultant to discuss the results and any recommended next steps.