Contents:
- Medical Video: Should You Get Genetic Testing During Your Pregnancy?
- The pros and cons of genetic screening for pregnant women
- Types of screening tests commonly performed on pregnant women
- 1. Sequential screen
- 2. Maternal serum quad screen
- 3. 20-week ultrasound
Medical Video: Should You Get Genetic Testing During Your Pregnancy?
In general, pregnant women are offered a variety of genetic screening tests during the first month until the third month of their pregnancy. Why should a genetic screening test be done? Genetic screening tests can evaluate your fetus whether your fetus has a risk of genetic disorders. Screening tests are usually done around 10-13 weeks during pregnancy. In addition, a genetic screening test can also be done in the second trimester.
Information from the results of the screening test, combined with other risk factors such as the age of the mother and history of hereditary disease, is used to calculate the possibility of the fetus born with a genetic disorder, such as Down syndrome, cystic fibrosis, tay-sachs diseaseor sickle cell anemia.
Defects in the fetus can occur at any time during pregnancy, but usually this happens in the first trimester, where the baby's organs begin to form.
This screening test can help prospective parents to see if their baby has a low or high risk of developing abnormal chromosomes. However, the only way to know for sure whether your baby has a genetic disorder is to do a genetic diagnostic test.
The pros and cons of genetic screening for pregnant women
When a prospective mother is facing a dilemma about whether to undergo a screening test, here are the questions you need to ask yourself:
- First, "Do I want to know before my baby is born that my child might have an abnormal chromosome?"
- Second, "If the results of the tests are positive, what will I do?"
One of the advantages of doing genetic screening is that prospective parents can find out whether your child will have a genetic disorder.
But on the other hand, if the results of this test are positive, you have to know how you will react. You can go to genetic counselor to conduct genetic diagnostic tests that can provide more accurate results.
Keep in mind that genetic screening can give false positive results. Which means, it is possible that these false positive results give false expectations to prospective parents, they think their children will be born disabled even though they are not. However, it is also possible that screening genetics do not detect chromosomal abnormalities when they actually exist.
So it is not recommended for pregnant women to take steps to abort the pregnancy due to the positive results of the genetic screening test. Further testing is needed to confirm the diagnosis of this test.
Types of screening tests commonly performed on pregnant women
1. Sequential screen
Sequential screen is a screening test that combines 3 information obtained from 2 different pregnancy periods to determine whether the fetus has a risk of developing Down syndrome, trisomy 18, and open neural tube defect (for example spina bifida). The first sequential screen is done in the first trimester, around 10-13 weeks of gestation. When you will get a sequential screen action, you will meet with genetic counselor. Then, you will undergo ultrasound. With ultrasound, measure the fluid that is behind the neck of the fetus (nuchal translucency) After ultrasound, the mother's blood will be taken. Information from ultrasound results and from the mother's blood will be combined to give the results of the first stage, which can usually be seen a week later. This result will give you specific results about the risk of your fetus suffering from Down syndrome and trisomy 18.
If the results show a high enough risk and make you uncomfortable, you may be immediately offered to undergo a genetic diagnostic test to provide definitive answers. However, if you do not choose to do a genetic diagnostic test after the first results are out, then you will go back to undergoing sequential screen in the second trimester, usually around 16-18 weeks of gestation. However, this time you only take blood. Later, information on this mother's blood and ultrasound results from the first trimester are combined, and the final results of this test will come out a week later. With this final result, you will find out the possibility of your child suffering from Down syndrome, trisomy 18, and open neural tube defects like spina bifida. From this result, you can decide whether you will undergo further testing or not.
2. Maternal serum quad screen
Maternal serum quad screen, or usually abbreviated as quad screen, is a type of screening test that looks at certain protein levels that appear during pregnancy, which are found in the mother's blood during the second trimester. Quad screening only requires maternal blood samples, which are usually taken at the time of 15-21 weeks of gestation. From the results obtained, you can decide whether you will do further tests or not. Quad screening does not produce results as accurate as sequential screen. Usually, quad screening is offered to pregnant women who have not undergone sequential screen in the first trimester of their pregnancy.
3. 20-week ultrasound
20-week ultrasound is an ultrasound that is run in the second trimester, usually 18-22 weeks of gestation. Please note that this ultrasound is different from ultrasound which is done to determine the sex. Ultrasound is done to determine whether the fetus is at risk of being born with a disability. Through ultrasound, you will see the presence of structures in your child's birth defects, such as abnormal heart, kidney problems, abnormal limbs, and abnormal ways when the brain begins to form. Besides being able to see the signs that have been mentioned, this ultrasound can also function as a screening test to see some genetic disorders such as Down syndrome. If you find an abnormality, then the doctor or genetic counselor will discuss these results with you to help you understand the risks to your pregnancy based on the results of this test, and talk to you about the possibility of further testing with amniocentesis (one type of genetic diagnostic test).
Uniquely, most babies who look "abnormal" by ultrasound are actually born healthy and without genetic disorders. Conversely, babies who look "normal" on ultrasound are actually born disabled or have genetic disorders that cannot be detected by ultrasound.
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