How is amniocentesis done?

The clinician first checks the baby's position, the placenta and a suitable pocket of fluid. After cleaning the skin, they guide the needle while watching it on the ultrasound screen, collect fluid in a syringe and then remove the needle. The sample is sent to a laboratory for the tests agreed with you.

You lie on an examination couch with your abdomen exposed. Gel is placed on the skin for the ultrasound, and the baby's heartbeat is checked before and often after sampling. You may feel pressure, a brief sting or cramping as the needle passes through the abdominal wall. The needle does not pass through the vagina.

Amniotic fluid contains cells shed by the baby as well as substances that can be measured. The exact laboratory analysis depends on the reason for testing, so the results available and their timing can differ.

Tell the maternity team about medicines, allergies, your blood group if known, previous pregnancy complications and any infection symptoms. Follow the clinic's instructions about whether your bladder should be full or empty. Arrange a calm period afterward because mild lower-abdominal cramping can occur.

Before consenting, clarify what is being tested, what a positive, negative or uncertain result could mean, and how the findings might affect pregnancy care. Do not stop prescribed medicine unless the clinician responsible for it advises you to do so.

Seek prompt maternity advice after the procedure if you have fluid leaking from the vagina, vaginal bleeding, fever, chills, worsening or persistent abdominal pain, regular contractions, or you feel generally unwell. If you already feel the baby moving, report a clear reduction in the usual movement pattern. Use emergency services for severe symptoms or if your maternity team directs you to do so.

Ask why amniocentesis is being offered now, which laboratory tests will be performed, when each result may arrive, and whether genetic counselling is available. It is also useful to ask who to contact after the procedure and which activity or travel guidance applies to you.