What is Amniocentesis?
It is an invasive procedure for prenatal diagnosis of chromosomal disorders or genetic diseases.
Chromosomes carry genes that pass certain characteristics from parents to their children. Genetic disease usually occur when there is missing, extra or irregular portion of chromosomal DNA.
Down Syndrome is the most common chromosomal disorder. It causes mental disability and other health problems such as heart defect.
How is Amniocentesis done?
Using ultrasound as a guide, the doctor will insert a thin needle through the mother’s belly into the womb and extract a small amount of amniotic fluid (about 20cc) surrounding the fetus. Local anaesthesia is commonly used.
After the fluid has been extracted, it will be sent to the laboratory for genetic analysis. The whole procedure takes only 10-15 minutes and is performed as outpatient procedure.
Who should consider Amniocentesis?
It is offered to women:
- Whose First Trimester Screening (OSCAR Screening) or NIPT (Harmony) test result shows a “High Risk” for Trisomy 13, 18 or 21.
- When both parents are Thalassaemia carries or carriers of a known genetic disease.
- With a previous child born with Down Syndrome or other genetic disorder.
- If family history of genetic disorder or carrier.
- If an early ultrasound report shows that the fetus has structural defects which are associated with chromosomal abnormalities.
When is Amniocentesis done?
It is performed from 16-20 week of pregnancy.
What are the risks of Amniocentesis?
The risk of amniocentesis-related miscarriage is reported 0.3-0.5%.
When will the Amniocentesis results be available?
It usually takes 2 weeks to complete the laboratory tests.
Do I need to fast before the Amniocentesis procedure?
Fasting is not required. A light meal can be taken before the procedure.
Any precautionary measures to take after the Amniocentesis procedure?
The mother will be advised to rest and avoid heavy lifting for the next 1-2 days.
What warning signs after the procedure?
The mother will be advised to look out for:
- Pain in the shoulder
- Lower abdominal pain or cramps
- Vaginal bleeding
- Leakage of fluid from vagina
If you have any of these symptoms, go to the emergency clinic immediately as these could mean threatened miscarriage.
If the result is normal, does it mean that the baby will be born healthy with no birth defects?
Amniocentesis can detect almost all chromosomal abnormalities and certain specific genetic diseases. However, it cannot guarantee a healthy baby as most birth mal-developments are structural problems.
If the result is abnormal, what are my options?
Your doctor will provide you with more information about the report and discuss the options with you. You may then decide whether to continue with the pregnancy.