What should you know about reason for amniocentesis?

Amniocentesis is offered to examine fetal genetic or chromosome information when screening, family history or ultrasound findings raise a specific question. A fine needle collects amniotic fluid through the abdomen with ultrasound guidance. The procedure is diagnostic for the conditions tested, while screening tests estimate likelihood rather than confirming a diagnosis.

Your maternity team may discuss amniocentesis after a screening result, an ultrasound finding, a known inherited condition in the family, or a previous pregnancy or child affected by a genetic condition. It can test fetal cells in the fluid for selected chromosome or genetic conditions. The exact panel and timing vary, so ask what the test can and cannot answer in your situation.

Ask what prompted the offer, how the sample will be collected, when results may arrive, and what choices follow each possible result. The procedure, benefits, limitations and risks should be explained in language you understand. [Chorionic Villus Sampling](/treatments/pregnancy-and-birth-care/chorionic-villus-sampling/) may be an alternative at an earlier stage, while [NIPT](/treatments/pregnancy-and-birth-care/nipt/) is a screening option. Do not feel pressured to decide before your questions are answered.

Follow the instructions from your maternity team. Contact them promptly for bleeding, fluid leakage, fever, worsening abdominal pain, contractions or feeling unwell after amniocentesis. Use emergency care for severe pain, heavy bleeding, fainting or a serious sudden deterioration. The team can tell you which symptoms are expected locally and how to reach them.

Ask which condition is being investigated, whether the result is diagnostic, how long each result takes, and whether a rapid or detailed analysis is planned. Discuss alternatives, timing, procedure-related risks, support for decision-making and who will explain the result to you.