Pregnancy is a wonderful phase in a woman’s life. It may be filled with concerns about health of the unborn child. Though several tests and scans may be performed to keep on the tab on the health of the unborn child. One of the tests which is recommended is the pregnancy double marker test.
What is a pregnancy double marker test?
A double marker test or maternal screening can be used to determine any complications and its possibilities with the unborn child. It is a test part of the first trimester screening. Though a predictive test in nature, it tracks the likelihood of any chromosomal abnormalities.
When is a pregnancy double marker test required?
This test is prescribed during the first trimester in to order to avoid any unforeseen complications post child birth. The screening includes checking blood levels for both beta-human chorionic gonadotropin and pregnancy related protein such as PAPP-A (pregnancy related plasma protein-A).
The window to undergo the screening is relatively small and the procedure is performed between gestational age of 11 and 14 weeks.
The test is not mandatory; however, it is recommended for individuals over the age of 35 or who have a history of any chromosomal abnormality. Chromosomal abnormalities which can be identified earlier with this test include down/ Turner syndrome.
Procedure for double marker test screening
The test is easy to perform where a blood sample is drawn and no such risk is involved. In very rare cases, a female might experience hematoma formation, bruising or infection at the site of the needle prick.
The double marker test is interpreted along side an ultrasound test also known as nuchal translucency test (NT) scan to determine the clear tissue at the back of baby’s neck.
The placenta produces a hormone known as free beta hCG where higher levels of free beta hCG will indicate a higher risk of Down syndrome and Edwards syndrome.
On the other hand, PAPP-A is an essential plasma protein wherein low levels of the protein can indicate a higher risk of Down syndrome
Edwards syndrome or trisomy is a chromosomal condition which is characterised by an additional chromes.
The levels of hCG and PAPP-A may either be lower or higher than normal in pregnancy with the chromosomal abnormalities.
How can the procedure be beneficial?
The procedure can detect Down syndrome, trisomy 18 which causes mental retardation and trisomy 21 which causes heart issues, mental disorders and other health conditions affecting vital organs of the newborn child.
As it is a non-invasive blood test, there are no such risks associated with the double marker test. But you need to follow the doctor’s instructions in case there are any concerns related to the tests.
What can the results of the double test marker indicate?
A pregnant woman may have the following results-low, moderate and high risk. If an expectant mother receives a low or negative result, it means that the baby has low probability of chromosomal abnormalities. However, if the results are in normal range and other indicators such as age, family history are a concern, then the doctor may recommend further testing.
You need to understand that a low risk result doesn’t imply that the urban will be without any chromosomal defects. The test only looks for indicators such as Down syndrome, trisomy 13 and 18 and doesn’t indicate any other specific conditions.
Advantages of a double marker test
-It helps to find out the trisomy of the chromosome number 13 which is responsible to cause mental retardation of the infant and severe birth defects.
-It is also helpful to detect chromosomal aberration resulting in down’s syndrome
-It helps to detect high risk factors of pregnancy which can also be detrimental to the mother’s health also
-The test has good detection rates
-In case a mother is positive after the test for the abnormality, it will provide couples the time to analyse the entire situation. It also helps to consider whether they are willing to go for further tests.
Abnormal results for the double marker test
If your results are in the moderate to high risk category, you can consult a genetic counsellor to know more. To confirm the same, you can also undergo non-invasive prenatal testing like amniocentesis to verify the condition. Being aware about that you will have a baby will special needs, you will be prepared and provide you the time to support you need to provide the child.
What are the normal values in double marker test?
For all age groups, the double Marker test average value of the hCG is 215 to 2419 ng/ ml, and the PAPP is 1 medium of median (MoM).
What is the difference between NT scan and double marker test?
A NT or nuchal translucency scan to assess the baby’s risk of having any chromosomal abnormality or heart defects. Doctors may combine the results of both tests to reach a conclusion. A NT scan helps to collect the real time images of the baby. It can help to provide nasal bone and neck measurements, to identify an abnormality.
Difference between double marker and quadruple test
The double marker test analyses the level of hormones PaPP and HCG, whereas the triple marker test analyses the levels of hormones such as alpha fetoprotein, HCG and Estriol. Whereas the quadruple test is more sensitive and is recommended during the second trimester.
If your baby has a high risk of chromosomal abnormalities, the HCG levels will be high and that of PAPP, estriol will be low. Based not he risk the category mother falls in, the doctor might suggest further tests to confirm.
What if the double marker test is positive?
The likelihood of a child having any condition may be estimated using the double marker test ratios. Suppose the test turns out to be positive. In that case, the doctor may suggest you to some additional diagnostic procedure such as chorionic villus collection or amniocentesis to determine the source of the issue.