Every pregnancy is associated with a small risk of chromosomal disorders, which are abnormalites involving the genetic makeup of the baby. The most common disorder is Down Syndrome where there is excessive genetic material from an extra chromosome 21. Likewise, excessive genetic materials from extra chromosome 13 and 18 result in Patau syndrome and Edward syndrome respectively.
These disorders result in mental retardation and frequently, heart defects and other physical abnormalities. Screening tests are available to assess the risk of having the above disorders in each pregnancy.
Nuchal Translucency Screening
Nuchal translucency (NT) describes a fluid-filled (sonolucent) area at the back of the neck (nuchal region) of the fetus.
Measuring the thickness of this area at a specific place is called NT measurement. This provides an assessment of the individual specific risk of having a baby with Down syndrome, Patau and Edward syndromes.
This test is done between 11 weeks, 3 days and 13 weeks, 6 days of pregnancy. Done through an abdominal ultrasound scan, the detection rate for these chromosomal disorders is about 80%.
Nuchal Translucency and First Trimester Serum Screening (Combined Screening)
Combining both nuchal translucency screening and first trimester serum screening (blood test), it measures two hormones called the free beta HCG (human chorionicgonodotrophin) and PAPP-A (pregnancy-associated plasmaprotein-A).
The detection rate for Down syndrome, Patau and Edward syndromes is approximately 90%.
Triple Test or Triple-marker Test
This is a screening for Down syndrome. In this test, 3 hormones are measured – AFP (alpha fetoprotein), HCG and Estriol. It also screens for risk of neural tube defects like spina bifida.
The test is usually done between 14 and 20 weeks of pregnancy and the detection rate for Down Syndrome is about 60% – 65%.
A more advanced type of ultrasound can offer crystal clear realistic 3D images of the baby, sometimes with photo-quality details, using special imaging software. Our Antenatal Diagnostic Centre is equipped with a state-of-the-art 3D/4D ultrasound machine.
3D scans are realistic, still pictures of your baby and are useful in helping doctors to look at the heart and other internal organs. 4D scans are 3D images of your baby while he is moving.
3D scans are best done around the 7th month (28 weeks) to detect any structural abnormalities. It is also a unique way for you to bond with your baby and keep it as a lifelong momento.