At The Choolani Clinic, we provide non invasive prenatal screening tests for mothers with anticipated high risk pregnancies. Non-invasive means no deployment of any invasive means near the fetus, more specifically, no needling near the fetus.These tests are safe and highly accurate in detecting fetal abnormalities such as Down Syndrome, Edward Syndrome and Turner Syndrome.
Before these tests became available, typically, patients aged between 35 and 45 would undergo invasive tests such as Amniocentesis or CVS (Chorionic Villus Sampling). An amniocentesis is usually performed between the 16th and 20th weeks of pregnancy, whilst a CVS can be done between the 11th and 15th weeks. Needles are inserted in the woman's uterus to draw out either amniotic fluid (amniocentesis) or tissue from the placenta (CVS). The fluids contain cells from the baby which are examined for the chromosomal abnormality.
With non-invasive prenatal testing on the other hand, a simple blood sample is taken from the mother’s blood at around week 12, and analysed for cell free fetal DNA. This is considered to be a more direct and accurate form of obtaining information on the fetus, as opposed to visual screening methods such as ultrasound, which is reliant on the skill of the operator. Some tests are able to detect chromosomal abnormalities in the fetal cfDNA fragments with more than 99% accuracy, rendering it a near diagnostic.
How does it work?
The test is based on next generation sequencing technology called Massively Parallel Sequencing (“MPS”) that analyzes circulating cell-free fetal DNA extracted from a maternal blood sample, and measures how many copies of fetal trisomies are present. This is followed by an in-depth bioinformatics analysis of fetal DNA ratios. It is able to detect with near 100% accuracy for Trisomies 21 (Down syndrome), Trisomy 18 (Edwards Syndrome) and Trisomy 13 (Patau Syndrome).
How accurate is it?
The benefit of this screen test is the high detection rates of more than 99% and low false-positive rates of less than 1% with no risk to the pregnancy.
99.1% detection for Down syndrome
99.9% detection for Edwards Syndrome
91.7% detection for Patau Syndrome
Who is eligible
Patients who meet the one or more of the following criteria:
Age at pregnancy (35 years or older at the time of delivery)
Family history of genetic abnormalities
Abnormal prenatal ultrasound findings
Increased risk based on screening results
It is anticipated that the test will very significantly reduce the number of invasive diagnostic tests such as Amniocentesis and Chrorionic Villus Sampling (CVS) by as much as 95%. These invasive tests carry a risk of miscarriage of about 1 in 100.
The Clinic is dedicated to providing patients with the latest and safest technologies in prenatal care, and recommends these new and non-invasive tests for patients.