Why do pregnant women need to do genetic screening & bull; hello healthy

In general, pregnant women are offered various kinds of genetic screening tests during the first month to the third month of their pregnancy. Why is a genetic screening test done? Genetic screening tests can evaluate your fetus whether your fetus is at risk for genetic disorders. Screening tests are usually done around 10-13 weeks of pregnancy. In addition, genetic screening tests can also be done during the second trimester.

The information from the results of the screening test, combined with other risk factors such as maternal age and a history of hereditary disease, is used to calculate the likelihood that the fetus will be born with a genetic disorder, such as Down syndrome, cystic fibrosis, tay-sachs disease , or sickle cell anemia.

Fetal defects can occur at any time during pregnancy, but usually it occurs during the first trimester, when the baby's organs begin to form.

This screening test can help expectant parents to see if their baby has a low or high risk of contracting an abnormal chromosome. However, the only way to know for sure if your baby has a genetic disorder is to do a genetic diagnostic test.

Pros and cons of genetic screening for pregnant women

When a mother-to-be is facing a dilemma whether to undergo a screening test, here are questions you need to ask yourself:

• First, "Do I want to know before my baby is born that my child may have an abnormal chromosome?"
• Second, "If the result of the test is positive, what will I do?"

One of the advantages of carrying out genetic screening is that prospective parents can find out if your child has the possibility of having a genetic disorder later.

But on the other hand, if the result of this test is positive, you have to know how you will react to it. You can go to genetic counselor to do a genetic diagnostic test that can give a more accurate result.

Keep in mind that genetic screening can return false positives. Which means, it could be that this false positive result gives wrong expectations of prospective parents, they think their child will be born with disabilities when they are not. However, genetic screening may not detect chromosomal abnormalities when they do exist.

So it is highly discouraged for pregnant women to take steps to terminate their wombs due to positive results from genetic screening tests. Further tests are needed to confirm the diagnosis of this test.

Types of screening tests that are usually performed on pregnant women

1. Sequential screen

Sequential screen is a screening test that combines 3 information obtained from 2 different gestational periods to find out whether the fetus is at 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 will get the sequential screen action, you will meet with genetic counselor . Then, you will live ultrasound . With ultrasound, the fluid that is behind the neck of the fetus is measured (nuchal translucency). After the ultrasound, the mother's blood will be drawn. The information from the ultrasound results and from the mother's blood will be combined to give the first stage results, which can usually be seen a week later. These results will give you specific results about your fetal risk for Down syndrome and trisomy 18.

If the results show a high enough risk and make you uncomfortable, you may immediately be offered a genetic diagnostic test to provide a definite answer. However, if you do not choose to do a genetic diagnostic test after the first results come out, then you will return to undergoing sequential screens in the second trimester, usually around 16-18 weeks of gestation. However, this time you only need to take blood. Later, this maternal blood information and the 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 likelihood that your child has Down syndrome, trisomy 18, and open neural tube defects like spina bifida. From these results, you can decide whether you will undergo further tests 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 the levels of certain proteins that appear during pregnancy, which are found in the mother's blood during the second trimester. Quad screening only requires a mother's blood sample, which is usually taken at 15-21 weeks of gestation. From the results you get, you can decide whether you will do further tests or not. Quad screening is not as accurate as a sequential screen. Usually, quad screening is offered to pregnant women who have not undergone sequential screens in their first trimester of pregnancy.

3. 20-week ultrasound

A 20-week ultrasound is an ultrasound performed during the second trimester, usually 18-22 weeks of gestation. Please note that this ultrasound is different from the ultrasound that is done to determine gender. This ultrasound is done to find out whether the fetus has a risk of being born with defects. Through ultrasound, you will see the presence of structures that indicate your child will be born with a defect, such as an 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 serve as a screening test to see some genetic disorders such as Down syndrome. If any abnormalities are found, the doctor or genetic counselor will discuss these results with you to help you understand about the risks to your pregnancy based on the results of this test, and talk to you about the possibility of further testing with amniocentesis (a type of genetic diagnostic test).

Uniquely, most babies who look "abnormal" on ultrasound are born healthy and without genetic abnormalities. Conversely, babies who look "normal" on ultrasound are instead born with defects or have genetic disorders that the ultrasound cannot detect.