If you are about to complete your first trimester then your doctor must have asked you to get level 1 ultrasound NT NB scan and double marker test to check your baby’s risk of certain birth defects, such as Down syndrome, Edward’s Syndrome and many other chromosomal abnormalities as well as heart problems.
When to get level 1 NT NB scan done?
Your doctor will guide you well for this. You should get this done between 11th to the 13th week of pregnancy. So remembering dates are very much important during this journey. I use clue app to manage the dates
How NT NB test is done?
This is a non-invasive ultrasound where they measure the length of the Nasal Bone (NB) and Nuchal Translucency (NT) length in the first trimester of pregnancy. It is done on pregnant women between 11-13.6 weeks gestational age to detect the risk of chromosomal abnormality. The scan is done by a Radiologist or gynecologist where they do the precise scan and check the skin in the back of the neck which forms a lucent band on the scanned image and this is measured. After the scan, they give you the ultrasound report with analysis.
What is double marker test and how it is done?
A double marker screening test is done along with the NT NB scan and it is advised to get the both test done on the same day to get a good result. In double marker test blood sample of the pregnant lady is taken to measure the levels of β hCG (human chorionic gonadotropin hormone) and the PAPP – A (pregnancy-associated plasma protein). This test is used to detect the likelihood of having a child with Down syndrome. It is commonly done in women over the age of 35, as there is an increased chance of having a child with Down syndrome as the maternal age increases.
If your double marker test indicates the high risk then you should consult your gynae again and she will advise you to go for next level tests like CVS or amniocentesis basis the analyis.
A β hCG value falling in the range of 25700 – 288000 mIU/ ml is considered normal. (Between 8 to 12 weeks of Pregnancy)
A normal PAPP – A result in the first trimester is usually a value that is greater than 0.5 MoM.
What if I missed my double marker test?
You should not worry at all if you have got your NT NB scan done and missed the double marker test. If your NT NB scan is normal then you can relax and go for the quad marker screening test (quad screen) which is also a blood test done typically between the 15th and 20th weeks of gestation.
Is it really important to get this test done?
In my opinion, one should definitely go for this test to rule out the chances of chromosomal abnormalities in your child.
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