Clinical Definition
The first trimester of pregnancy is an exciting time for expectant mothers. Your calendar will be marked for visits to the gynaecologist, scans and several tests needed to be done. It is advisable for expectant mothers to go through genetic testing and diagnostic testing during pregnancy. Genetic tests are conducted during the first trimester to assess the baby’s risk of congenital disabilities and mother’s risk to any potential infection. Screening tests and diagnostic tests are two genetic tests done during pregnancy. Screening tests are done to diagnose any health hazards that could affect the baby, like infections, diseases, Down’s Syndrome or any physical abnormalities.
Why Get Tested
As a mother or parent, you would want to know the chances of your baby developing a serious health condition and the amount of risk involved. It is possible to check if the baby is at risk with the help of screening tests. Screening tests are a combination of blood tests and an ultrasound. Both of these together assess if the baby is at risk of developing a genetic disorder or birth defect. It also tells you if you have multiple pregnancies( for, eg, twins). The results of this test determine the need for a diagnostic test. It is advisable to have this test in the first trimester as it will help to diagnose the problem really early.
When To Get Tested
It is recommended that screening blood tests for HIV, Hepatitis B and Syphilis should happen as early as possible to decide the specialist care and treatment to be offered to protect your health. Screening tests for birth defects like Down’s Syndrome will happen at the time of the scan, around 11 to 14 weeks of pregnancy. Screening for abnormalities is done around 18 to 21 weeks of pregnancy at the time of mid-pregnancy scan.
Sample Required
- A sample of the blood is collected at the pathology centre between 9 to 12 weeks of pregnancy. This checks the levels of B-HCG and PAPP-A hormones to indicate a chromosomal condition
- An ultrasound (USG Test) is done between 11-13 weeks to measure the thickness of fluid in the area (known as nuchal translucency) behind the baby’s neck. The USG also takes measurements to calculate the baby’s gestational age.
A computer program combines these test results with your age, weight and baby’s correct gestational age to identify the risk of Down Syndrome, Trisomy 18 and Trisomy 21.
Preparation
The test is non-invasive and preparing for it is very easy. It just involves a simple blood sample drawn from the vein and an ultrasound which lasts about 20 minutes.
How To Interpret The Results
- “Not at an increased risk” means the risk of the baby having Down’s Syndrome or any other birth defect is low ( less than 1 in 300)
- “At increased risk” means the risk of the baby having Down’s Syndrome is greater than 1 in 300.
Results are available within a week and the doctor will tell you if a physical abnormality has been found and a diagnostic test will be recommended to confirm if the baby has Down’s Syndrome.
When Do You Need Us?
The blood test needs to be taken between 9-12 weeks of pregnancy. You will be battling with morning sickness, fatigue and several other pregnancy-related symptoms. This is where we can help. Our lab assistants will come and collect your blood sample to save you the trouble of walking into a pathology lab when you are busy dealing with pregnancy symptoms. A USG Test at home can also be requested as per your convenience.
How We Can Help
Booking a test just got easy. You can simply call us or book online through our portal. Get your test samples collected at your doorstep or office or a get a USG Test at home. You do not even have to come and collect your results as they will be sent via email.
Summary
Screening tests during the first trimester, a combination of foetal ultrasound and maternal blood testing determine the likelihood of an expectant mother having a baby with certain conditions related to infections and congenital disabilities. Screening tests are less invasive than diagnostic tests. Screening tests may be used singularly or in combination with other tests. Screening tests are done routinely in the first trimester, and both screening and diagnostic tests cannot detect all health conditions.
References:
http://healthywa.wa.gov.au/Articles/S_T/Screening-tests-in-the-first-3-months-of-pregnancy
https://www.stanfordchildrens.org/en/topic/default?id=common-tests-during-pregnancy-85-P01241
https://www.mamanatural.com/first-trimester-tests/
https://www.nhs.uk/conditions/pregnancy-and-baby/screening-tests-abnormality-pregnant/
