Amniocentesis
What is Amniocentesis?
Amniocentesis is an invasive diagnostic procedure that involves the examination of cells in the amniotic fluid from around the baby. If indicated, it is generally done between 15 -19 weeks of pregnancy. The cells in the amniotic fluid originate from the baby and so the chromosomes present in these cells are the same as those of the baby.
Why is an amniocentesis offered?
- Positive screening test including nuchal translucency risk assessment and/or NIPT
- Maternal age: some women older than 35 year declined screening tests in lieu of a definitive test
- Previous history of an affected child, parental chromosomal abnormalities or rare genetic diseases
How is amniocentesis performed?
You will have the procedure explained to you by our specialist doctor and sign a consent form. Amniocentesis involves passing a thin needle into the uterus in order to aspirate a small amount of amniotic fluid. The needle is carefully observed using ultrasound to ensure correct placement.
The amount of fluid removed by amniocentesis will reaccumulate within a few hours.
The procedure lasts about 5 minutes and afterwards we check that the fetal heart beat is normal.
What should I expect after amniocentesis?
We recommend that someone accompany you home after the test and that you take it easy for the rest of the day. There's no need to stay in bed, but it's best to rest at home and avoid any strenuous activities, including lifting heavy objects.
For the first couple of days, you may experience some abdominal discomfort or cramp-like period pain. Taking simple pain relief, such as paracetamol, can help ease this. If you experience significant pain, heavy bleeding, fluid loss from the vagina, or develop a fever, please seek medical advice promptly.
How is the amniotic fluid analysed?
Cell Culture
Fetal cells are cultured in the laboratory to allow them to grow and divide, ensuring there are enough cells available for thorough analysis.
Genetic Testing
Karyotyping involves examining the chromosomes in fetal cells to identify any abnormalities, such as extra or missing chromosomes.
FISH (Fluorescent In Situ Hybridization) is a technique that uses fluorescent dyes to highlight specific chromosomes regions,
enabling faster detection of certain chromosomal abnormalities.
Chromosome micro-array testing(CMA): is a genetic test that can detect small changes in DNA, like missing or extra pieces.
When will I receive my results?
Results are usually available between 10 and 21 days, depending on how quickly the cells grow in the laboratory. You will be contacted by phone once the results are ready, and a written report will also be sent directly to your doctor by the laboratory.
What are the risks associated with amniocentesis?
There is a small risk of miscarriage associated with amniocentesis—approximately 0.5%, which is similar to the risk with chorionic villus sampling (CVS). If a miscarriage were to occur as a result of the procedure, it would most likely happen within the first five days following the test.
