Amniocentesis

Amniocentesis

What is amniocentesis?

Amniocentesis stands as one of several diagnostic tests available during pregnancy. Its purpose is to identify potential chromosome abnormalities in the unborn child, which could include Down's syndrome or other congenital issues.

During amniocentesis, a sample of the amniotic fluid surrounding the fetus is extracted and analyzed. This procedure typically commences from the 15th week of pregnancy onward.

When is amniocentesis offered?

Amniocentesis is provided during pregnancy under various circumstances:

• When a woman is deemed at elevated risk due to a serum screening test, which evaluates pregnancy hormone levels in her blood. These results, combined with the mother's age, help calculate the likelihood of Down's syndrome.

• If a woman has previously experienced a pregnancy affected by a chromosomal or genetic disorder, she may be considered at high risk.

• Following an ultrasound examination that detects features or abnormalities suggesting an increased risk of a chromosome abnormality.

• Upon a woman's request due to concerns about her baby's potential chromosome abnormality.

• In some cases, amniocentesis is needed to investigate and manage conditions such as rhesus diseases during pregnancy. In such instances, the amniotic fluid is analyzed for its substances rather than specifically focusing on the baby's chromosomes.

How is amniocentesis performed?

Using ultrasound for guidance, a thin needle is inserted through the mother's abdomen into the fluid surrounding the fetus. Approximately 20ml of amniotic fluid is withdrawn and sent to a laboratory for analysis. The procedure typically lasts 5 to 10 minutes, causing only slight discomfort for the mother, with the fetus unaware of the process.

Following the procedure, the mother is advised to rest for the day and may experience mild cramping. Any bleeding or fluid leakage from the vagina should be reported to the hospital immediately.

If the mother has a rhesus-negative blood group, she will receive an injection of human anti-D immunoglobulin to prevent complications.

How long until the results are known?

A preliminary result may be available within 48 hours, with the final result typically confirmed within two to three weeks.

Is amniocentesis safe for the mother and baby?

Although amniocentesis carries a slight risk of miscarriage, it is generally considered safe. However, the mother should discuss any concerns with her obstetrician before undergoing the procedure.

How reliable are amniocentesis results?

While no test is 100% reliable, amniocentesis is highly accurate, with a 99.9% certainty in identifying chromosome abnormalities.

What if abnormalities are detected?

There is no treatment for chromosome abnormalities. Depending on the nature of the abnormality, termination of pregnancy may be offered. However, the decision to continue with the pregnancy ultimately lies with the parents, who should carefully consider the implications of abnormal results before undergoing amniocentesis.