Prenatal testing: Is it right for you?

The article was professionally consulted by Specialist Doctor I Pham Thi Yen - Obstetrician - Obstetrics and Gynecology - Vinmec Hai Phong International General Hospital.

Pregnancy is a very important but also full of worries for a woman. Most babies are born healthy, but prenatal testing (including prenatal screening and prenatal diagnostic testing) can provide valuable information about your baby's condition while still being born. still a fetus. Understanding the benefits and risks of these tests helps pregnant women make choices that are right for them.

Prenatal testing is classified into two main categories as prenatal screening tests and prenatal diagnostic tests:
Prenatal screening tests : prenatal screening tests can help identify the possibility that the fetus has certain birth defects (many of which are caused by genetic disorders). These tests include blood tests, specialized ultrasound, and prenatal acellular DNA screening. Prenatal screening is usually done during the first or second trimester of pregnancy. Antenatal screening test cannot be used as a basis for a definitive diagnosis, in case the results indicate a high risk of developing a genetic disorder, the specialist doctor will be responsible for consulting and discussing the implementation of the pregnancy test. Perform diagnostic tests to get an accurate conclusion. Prenatal diagnostic test: if the results of prenatal screening test show a problem, or the pregnant woman has risk factors (older pregnant woman, medical history, ...) If the fetus has a genetic disorder, the pregnant woman may consider using invasive prenatal diagnostic testing. The only way to get an accurate conclusion is to perform prenatal diagnostic testing. However, some prenatal diagnostic tests carry a small risk of miscarriage (such as chorionic villus sampling and amniocentesis).

Prenatal screening tests include:
Screening tests in the first trimester of pregnancy: in the first trimester of pregnancy, a specialist will order blood tests and ultrasound to measure the size of the space at the nape of the neck. of the fetus. In Down syndrome and some other birth defects (such as the heart, abdominal wall, and bones), the size of the space at the back of the baby's neck is abnormally large. These tests are usually done between the 10th and 13th weeks of pregnancy. Second trimester screening: During the second trimester, your specialist may order a blood test called the quad screen. It got its name because this test measures the levels of four substances in the blood, and is usually done between the 15th and 22nd weeks of pregnancy. The results of the test indicate the baby's risk of having certain genetic disorders, such as Down Syndrome. Screening also helps detect neural tube defects, which are serious abnormalities of the brain and spinal cord. Besides, between the 18th and 20th weeks of pregnancy, the doctor may order an ultrasound to detect most birth defects in the brain and spinal cord, maxillofacial, abdomen, heart and extremities. Prenatal DNA screening: Acellular DNA is a small amount of placental-derived DNA that enters a pregnant woman's bloodstream, and this blood test (usually done at the 10th week of pregnancy) checks for A cell-free DNA test in a pregnant woman's blood looks for an increased risk of certain genetic problems, such as Down Syndrome. This screening can also provide information about the sex and rhesus (Rh) blood type of the fetus. Acellular DNA screening is most appropriate for women who are at high risk of carrying a fetus with a chromosomal disorder, but not for women with multiple pregnancies.

The results of the prenatal screening test are expressed in terms of the degree of risk that the genetic disorder may occur:
A positive result means that the fetus has a higher risk of developing the genetic disorder than the level population mean, it is not certain that the fetus is sick. A negative result means that the fetus has a lower risk of developing a genetic disorder than the population average, but it does not mean that the fetus does not have the disease.

Pregnant women have the choice to perform prenatal screening tests to detect fetal abnormalities or not. Pregnant women will be carefully explained and consulted by a specialist about prenatal tests to consider and make decisions, especially when pregnant women perform screening to detect untreatable abnormalities. be in the fetus. Issues pregnant women should pay attention to consider include:
What will pregnant women do after receiving the results? Normal results will certainly relieve all anxiety. But if prenatal test results show there's a chance the baby might have a birth defect, you'll face many complicated and difficult choices, such as whether or not to continue with the pregnancy. If you look at it from another perspective, pregnant women will have the opportunity to prepare more carefully for the birth and growth of the baby later.
What are the prenatal test results? Some prenatal tests help detect treatable problems during pregnancy, and others help the specialist understand the problem and plan treatment immediately after the baby is born. born.
How accurate is the result? Prenatal screening is not perfect. The accuracy of the tests (false positives, false negatives) varies greatly from one test to another.
What are the risks of testing? Pregnant women should weigh the benefits and risks of prenatal tests, such as concerns, pain or even the risk of miscarriage, against the value of information from the test results. .
Pregnant women need to consider before making a decision. The specialist doctor will advise and explain carefully about the tests for pregnant women to understand and choose.
Vinmec International General Hospital offers a Package Maternity Care Program for pregnant women right from the first months of pregnancy with a full range of antenatal care visits, periodical 3D and 4D ultrasounds and routine tests to ensure that the mother is healthy and the fetus is developing comprehensively. Pregnant women will no longer be alone when entering labor because having a loved one to help them during childbirth always brings peace of mind and happiness.

Article referenced source: mayoclinic.org