Writer: Minseo Kim
Editor: Minjae Shin
In this test, a needle is inserted through the abdomen to obtain a small amount of amniotic fluid from the uterus. Doctors use ultrasound to guide the needle to an area away from the baby. Some of your baby's cells are in body fluids. They are extracted and tested for genetic abnormalities. (“Prenatal Genetic Screening – Pregnancy Info”)
A medical team member inserts a needle into a vein in your arm to take a sample. For newborn screening, a blood sample is taken by puncturing the baby's heel. For some tests, a swab sample is taken from the inside of the cheek for genetic testing.(“Genetic Testing - Mayo Clinic”)
What is prenatal genetic testing? (“Prenatal Genetic Screening Tests”)
Prenatal genetic testing provides parents with information about whether the fetus has certain genetic disorders.
What are the TWO main types of prenatal tests?
Prenatal screening tests (산전 선별 검사)Prenatal diagnostic tests (산전 진단 검사)
Types of screening tests
(Prenatal screening tests are usually offered during the first or second trimester. )
First trimester screening tests: During the first three months of pregnancy, your health care provider may give you blood tests and ultrasound to measure the size of the voids in the tissue in the back of your baby's neck. In Down syndrome and certain other conditions, the measure of nape translucency is unusually large.
Second trimester screening tests: During the second trimester, your healthcare provider will give you another blood test called a quad screen. This test measures the levels of four substances in the blood. Results indicate a risk of having a baby with certain chromosomal disorders, such as Down syndrome. This test may also help detect neural tube defects (severe abnormalities in the brain or spinal cord).
Prenatal cell-free DNA screening: This blood test examines fetal DNA in the mother's bloodstream to screen for an increased chance for certain chromosomal problems, such as Down syndrome. This test can also provide information about your baby's gender and rhesus (Rh) blood type.
(These tests include blood tests, a specific type of ultrasound and prenatal cell-free DNA screening. )
These tests can tell whether the fetus actually has a particular disorder. These tests are performed on cells from the fetus or placenta obtained through amniocentesis or chorionic villi sampling (CVS). The FAQ164 Prenatal Genetic Diagnostic Test focuses on these tests.
Invasive prenatal testing may be considered if screening tests indicate possible problems or if age, family history, or medical history indicates an increased risk of having a baby with a genetic problem.
Prenatal testing includes both screening and diagnostic testing. A screening test is not a diagnosis. They can provide information about your baby's risk of having certain disorders or conditions. Only diagnostic tests are conclusive and can determine whether the baby has a birth defect.(“Prenatal Screening and Diagnostics”)
Solve
Prenatal genetic screening and ultrasound results of a pregnant woman's blood can screen for aneuploidies in the fetus. a defect in the brain and spine called a neural tube defect (NTD); Some defects in the abdomen, heart, and facial features. This FAQ focuses on these tests. (“Prenatal Genetic Screening Tests”)
Normal results can relieve anxiety. However, if prenatal testing reveals that your baby has a birth defect, you may face difficult decisions, such as whether or not to continue the pregnancy. On the other hand, you might welcome the opportunity to plan ahead of time for babysitting.
Some prenatal tests detect problems that can be treated during pregnancy. In other cases, prenatal screening warns health care providers about conditions that require immediate treatment after birth.
Purpose of doing Prenatal Genetic Testing - The purpose of prenatal testing is to select and diagnose problems that may affect the health of the mother or baby, identify and respond to problems when they do exist, and assess the risk of developing chromosomal or genetic abnormalities in the child.
DATA
(“Pregnancy over Age 35: A Numbers Game | Your Pregnancy Matters | UT Southwestern Medical Center”)
While the total number of births has decreased, the rate of first childbirth among women over 35 has been steadily increasing since the 1970s.
Both baby and mother share the risks associated with being over 35.
Age 35 is set by the National Institutes of Health as the baseline for classification as 'elderly' during pregnancy.
As women get older, babies are at an increased risk of some complications.
Risks to the baby
A woman is born with all the eggs she will have. As she gets older, so does the egg. Older eggs are more likely to divide unevenly, resulting in extra chromosomes in the fetus. Down syndrome is an example of such a condition.
Risks to the woman
Additionally, women over the age of 35 are more likely to have underlying health problems, such as obesity or heart disease. Pregnant women with these medical conditions are at greater risk of complications than younger women who do not.
These conditions can also lead to premature births, low birth weight, or other complications.
Older women are twice as likely to miscarry or prematurely and nine times more likely to have birth defects than normal mothers.
Strength
Prenatal screening tests
This test measures the levels of four substances in the blood. Results indicate a risk of having a baby with certain chromosomal disorders, such as Down syndrome. This test may also help detect neural tube defects (severe abnormalities in the brain or spinal cord). (“Prenatal Testing: Is It Right for You?”)
It can identify whether a baby is likely to have certain birth defects, many of which are genetic disorders.
Prenatal diagnostic tests
Diagnostic tests are the only way to be sure of a diagnosis.
Economic
(“How Much Does Genetic Testing Cost for Pregnancy? | Genome Medical”)The cost of genetic testing for pregnancy varies from less than $100 to more than $1,000, but most tests are covered. If your pregnancy is considered high risk for a genetic or chromosomal condition, your insurance is more likely to cover the test, but many options are covered even in low-risk pregnancies.
Limitation
Prenatal screening tests
Screening tests cannot make a definitive diagnosis.
Prenatal diagnostic tests
Some diagnostic tests, such as chorionic villus sampling and amniocentesis, have a small risk of miscarriage.
Ethical
There are also concerns about the possibility of genetic discrimination in employment or insurance.
Family feud because of baby's gender (“What Are the Risks and Limitations of Genetic Testing?: MedlinePlus Genetics”)
Social
Of the 500,000 pregnant women who give birth every year, 70,000 undergo prenatal genetic tests. (https://www.joongang.co.kr)
MLA
“Prenatal Genetic Screening – Pregnancy Info.” Pregnancyinfo.ca, 2022, www.pregnancyinfo.ca/your-pregnancy/routine-tests/genetic-screening/.
“Genetic Testing - Mayo Clinic.” Mayoclinic.org, 2020, www.mayoclinic.org/tests-procedures/genetic-testing/about/pac-20384827.
“Prenatal Genetic Screening Tests.” Acog.org, 2020, www.acog.org/womens-health/faqs/prenatal-genetic-screening-tests.
“Prenatal Screening and Diagnostics.” Yale Medicine, Yale Medicine, 10 Dec. 2019, www.yalemedicine.org/conditions/prenatal-screening-and-diagnostics.
“Prenatal Testing: Is It Right for You?” Mayo Clinic, 2020, www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/prenatal-testing/art-20045177.
“Prenatal Genetic Screening Tests.” Acog.org, 2020, www.acog.org/womens-health/faqs/prenatal-genetic-screening-tests.
“How Much Does Genetic Testing Cost for Pregnancy? | Genome Medical.” Genome Medical, 2018, www.genomemedical.com/genetic-testing-pregnancy/cost/.
“Pregnancy over Age 35: A Numbers Game | Your Pregnancy Matters | UT Southwestern Medical Center.” Utswmed.org, 2014, utswmed.org/medblog/pregnancy-over-35/.
“What Are the Risks and Limitations of Genetic Testing?: MedlinePlus Genetics.” Medlineplus.gov, 2021, medlineplus.gov/genetics/understanding/testing/riskslimitations/.
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