Last Updated on July 9, 2022 by Dr. Neeraj Gujar
Table of Contents
Overview
You may be wondering what color hair will your baby have as you close out your first trimester. Are they going to look more like you? Are they as daring and fearless as your sister’s toddler?
These things may remain a mystery for a while. However, your OB/GYN might offer you some screenings or tests to help you learn more about your baby, including their sex.
The double marker test is one diagnostic tool. It involves giving blood to be tested for markers of certain chromosomal abnormalities.
A double marker test:
The double marker test is also known as maternal serum screening, this is a part of larger screening called the first trimester screening. This is not a definitive test. It’s instead a predictive test that reports the likelihood of chromosomal abnormalities.
This test specifically screens for blood levels both of free beta-human chorionic gonadotropin and pregnancy-associated plasma proteins A (PAPPA).
A typical pregnancy will have 22 pairs of autosomes along with XX sex chromosomes for female fetuses and 22 pairs of autosomes with the XY chromosomes for male fetuses.
Trisomy refers to chromosomal conditions in which extra chromosomes exist, such as:
- Down Syndrome. This common trisomy is also known as trisomy 21. This occurs because there’s an additional copy of chromosome no. 21.
- Edward’s Syndrome. These chromosomal abnormalities are common and involve an extra copy chromosome 18 or 13 (Trisomy 18 and Trisomy 13).
Pregnancies with these chromosomal anomalies may have abnormal levels of hCG or PAPP-A.
However, blood levels alone don’t produce your results. The blood test can be used in conjunction with an ultrasound called a Nuchal Translucency (NT scan), which examines the clear tissue behind your baby’s neck.
Also Read: Why Should a Beta-hCG Blood Test Be Done
Why Test Is Done?
Double marker testing and NT scan are not mandatory for the first trimester screening. But it is recommended if you are over 35 years old or have a history of certain conditions.
The result does not conclusively determine if the baby is suffering from any abnormalities, it just indicated increased risk of trisomy.
There are certain questions that you should ask yourself before going for the test:
- What would the results mean for your management of your pregnancy?
- Do you feel anxious about knowing about abnormalities?
- If you get a higher risk result, would you be willing to undergo more invasive testing?
It all comes down to personal choice and your health history.
When To Get Test Done?
The time frame for double marker testing is very limited. You will need to make an appointment with your healthcare provider for the double marker test at the beginning of the second trimester, or very soon after the first trimester. You’ll be having your blood drawn between the weeks 11 to 14.
How To Get Tested?
It is a simple blood test and it does not require any specific preparation. You can eat and drink normally before test. You just need to inform your doctor about any medication taken prior to the test.
During the Test
The order will be written by your doctor for you to submit to a laboratory. This is a non-fasting test. You may eat and drink as normal before your appointment, unless otherwise instructed.
The turnaround time for lab results varies between laboratories. Your results should be available within 3 to 7 days. It is possible to inquire if your clinic will contact you or if you should call in order to receive your results.
After The Test
The double marker test is safe. This is a noninvasive, routine blood test. There are minimum to no complications after the test. You should follow the instructions of your doctor and speak to your provider if you have any questions.
Test Results
The result will be low, moderate, or high risk.
Screen-negative (or low-risk): This a result that indicates that your baby has low chances of developing chromosomal abnormalities. However, a low-risk result does not necessarily mean that your baby will have no problems. It’s important that you note that the screening in first trimester is only for Down syndrome, trisomy 13 and trisomy 18 and not the others.
Moderate or normal result: Your result will be considered normal. Only if there are other indicators like family history, age etc. then the doctor may recommend another test.
Screen positive (high-risk): You may want to discuss your results with a genetic counselor if your screening is deemed high-risk for abnormalities. You can confirm your result with more specific and more invasive tests such as noninvasive pregnancy testing (NIPT) or amniocentesis. These tests can be risky for your pregnancy but they will give you a definitive result.
The double marker test is performed early in the pregnancy. This gives you the time to make decisions about medical treatment, further testing and overall management of your pregnancy.
Your risk can help you plan for the possibility that you will have a child with special need and provide the support you need.
Final Takeaway
To test or not test? Start by looking at the benefits and drawbacks of both the double marker and first trimester screening. Consider how this information could help you make a decision about further testing and the management of your pregnancy.
Talk to your healthcare provider about the test and its utility in light of your particular circumstances. To ensure a healthy pregnancy, it is important to maintain close contact with your healthcare provider.
Sources
- Alldred S, et al. (2015). Screening tests for Down syndrome in the first three months of pregnancy.
cochrane.org/CD011975/PREG_screening-tests-downs-syndrome-first-three-months-pregnancy - Mayo Clinic Staff. (2018). Down syndrome.
mayoclinic.org/diseases-conditions/down-syndrome/diagnosis-treatment/drc-20355983 - Facts about Down syndrome. (2019).
cdc.gov/ncbddd/birthdefects/downsyndrome.html - Mayo Clinic Staff. (2020). First trimester screening.
mayoclinic.org/tests-procedures/first-trimester-screening/about/pac-20394169 - Screening tests in the first 3 months of pregnancy. (n.d.).
healthywa.wa.gov.au/Articles/S_T/Screening-tests-in-the-first-3-months-of-pregnancy
