What is NIPT (New Prenatal Testing)?
NIPT (New Prenatal Testing) is a test that takes a sample of a pregnant woman’s blood and examines the DNA fragments of the fetus contained in it. DNA is like a blueprint filled with genetic information and is contained in cells called chromosomes. Genes in chromosomes are inherited from both the father and the mother. If there is an abnormality in the chromosomes, the baby in the womb may be born with a congenital abnormality.
NIPT can be performed by simply taking a blood sample from the mother and does not involve direct invasion (damage) of the fetus, so it is also called “non-invasive prenatal genetic testing.”
What can be learned from NIPT (new type prenatal testing)
Congenital anomalies can occur regardless of the age at which a baby is born, and are said to occur in 3-5% of all newborns. Of these, chromosomal disorders caused by chromosomal abnormalities account for approximately 25% of congenital anomalies.
NIPT (non-inferior prenatal testing) mainly tests for three chromosomal abnormalities: Down syndrome (trisomy 21 ), Edwards syndrome (trisomy 18) , and Patau syndrome (trisomy 13). Depending on the facility, it is also possible to check for all possible chromosomal abnormalities.
The three specific congenital anomalies are as follows:
| Down syndrome (trisomy 21) | Symptoms |
Growth failure, decreased muscle tone, and distinctive facial features ≪Complications≫ Heart diseases, digestive malformations, and other thyroid and otorhinolaryngological diseases, etc. |
|---|---|---|
| About prognosis |
They often attend support classes or special needs schools. They may also have great talent, such as in the arts. Lifespan is approximately 50 to 60 years. | |
| Edwards syndrome (trisomy 18) | Symptoms | Growth failure from the fetal period, problems with breathing and feeding < |
|---|---|---|
| About prognosis |
Delays in physical and intellectual development are observed. Breathing assistance may be required. There are many cases where the fetus dies during pregnancy. 50% of cases die within one month after childbirth, and 90% die within a year. | |
| Patau syndrome (trisomy 13) | Symptoms |
Growth failure, breathing and eating disorders < |
|---|---|---|
| About prognosis |
Delays in physical and intellectual development are observed. Breathing assistance may be required. 90% of cases die within 1 year after childbirth | |
When can I receive NIPT (new prenatal testing)?
NIPT (new type prenatal testing) can generally be performed from 10 weeks and 0 days of pregnancy. There are several methods for prenatal testing, but Hiro Clinic NIPT can be performed as early as about 6 weeks of pregnancy (when pregnancy is confirmed by ultrasound examination).
At Hiro Clinic NIPT, we usually deliver results within 2 to 6 days (excluding some plans) after blood is drawn, so you can complete the test early in your pregnancy.
Risks of new prenatal testing
Many people are concerned about whether NIPT (new type prenatal testing) will have a negative impact on the health of the mother and child. The test only requires a blood sample from the pregnant woman, so there is almost no risk.
You may feel some pain when the needle is inserted into your arm, but it will not have a significant effect on your body. Both mother and child can receive NIPT without worrying about risks.
Definitive testing carries risks
NIPT (New Prenatal Testing) can be performed with a fairly low risk , but if the test is positive, a definitive test must be performed to make a definitive diagnosis. This is because there are rare cases of false positives. *
* The sensitivity of NIPT is said to be 96.5% for testing chromosome 21.
Definitive tests are a burden to the mother and child and carry the risk of miscarriage. Specific tests include the following:
Chorionic villus sampling
There are two ways to take the test: by inserting a needle directly into the abdomen, or by using a catheter through the vagina to take a sample. There is about a 1% risk of miscarriage, and other symptoms such as bleeding and water breaking may occur.
This is a test that examines cells called chorionic villi, which are part of the placenta during early pregnancy. Choriolic villi are cells that are part of the placenta during early pregnancy. The test is performed between the 11th and 14th weeks of pregnancy.
Chorionic villus sampling is performed by checking the position of the fetus using an ultrasound, but it is technically difficult and only a few medical institutions perform it.
Amniocentesis
This test involves inserting a needle into the pregnant woman’s abdomen to collect amniotic fluid. Because the fetus drinks and urinates in amniotic fluid, it contains cells derived from the fetus. The test involves culturing the cells contained in the amniotic fluid and then analyzing their genes, so it takes about three weeks for the results to become available.
Amniocentesis is a lower risk test than chorionic villus sampling, but there is a 0.2-0.3% chance of miscarriage or rupture of membranes. It is performed between the 15th and 18th weeks of pregnancy.
Please note that the confirmatory test for NIPT (new type prenatal diagnosis) is not something that must be taken even if the test is positive. Chorionic villus sampling and amniocentesis can be done at the parents’ request.
| Definitive test | ||
|---|---|---|
| Villus examination | Definitive diagnosis | Because the needle is inserted into the abdomen, there is a risk of miscarriage (1%). Performed between 10 and 13 weeks of pregnancy. |
| Amniotic fluid examination | Definitive diagnosis | Because the needle is inserted into the abdomen, there is a risk of miscarriage. (0.3%) Performed between 15 and 18 weeks of pregnancy. |
Risks of other prenatal tests
Some people may be concerned about the cost of NIPT (new prenatal testing) and the risks of definitive testing, and would like to know about other testing methods. Here we will look at the risks of tests other than NIPT.
Ultrasound examination (echo examination)
Ultrasound examinations are also performed during prenatal checkups, and are also called echo examinations. Specifically, an ultrasound device is placed on the pregnant woman’s stomach, and the echo is visualized. During the examination, the pregnant woman can check the monitor together with the doctor.
Ultrasound examinations are primarily performed to check the growth and development of the baby in the womb. However, they can also detect abnormalities in the baby, so in a broader sense they can be considered a form of prenatal diagnosis.
You can also have a fetal ultrasound screening test during the second trimester, which involves taking a longer ultrasound scan than normal prenatal screening to check for any problems with the fetus.
The test itself is non-invasive using ultrasound, so there is no risk to the baby. A gel is applied to the abdomen of the pregnant woman during the test, so she may feel cold.
If the test reveals an abnormality, a confirmatory test will be required to confirm the diagnosis.
Maternal serum marker testing
A blood test is used to check for the possibility of congenital abnormalities in the fetus. As with NIPT (non-invasive prenatal testing) , the test only involves drawing blood from the pregnant woman, so it is a low-risk test for the mother and child.
The test can tell you about the following possible diseases:
- Down Syndrome (Trisomy 21)
- Edwards syndrome (trisomy 18)
- Neural tube defects such as spina bifida and anencephaly (open neural tube malformations)
Maternal serum marker tests examine the components contained in the blood of pregnant women, and there are different types depending on which components are examined. Specific maternal serum marker tests include the following:
Quattro Test
This test checks for four components (hCG, AFP, uE3, and inhibin A) in the blood of pregnant women.
Triple Marker Test
This test checks for three components (hCG, AFP, and uE3) in a pregnant woman’s blood.
Regarding the Quadruple Test and the Triple Test, there is no significant difference in the accuracy of the two tests. The accuracy of a test refers to the rate at which a positive result is detected.
However, the results of serum marker tests are expressed as probability, making them difficult to interpret. In addition, the test is only intended for screening purposes, and a definitive test is required for a diagnosis.
Combined Inspection
This test involves two things: a maternal serum marker test and an ultrasound test. Since it is a combination of a blood test and an ultrasound test, there is almost no risk to the mother and child.
In the blood test, two fetal components (hCG and PAPP-A) contained in the pregnant woman’s blood are examined. The combined test can tell you about the possibility of the following congenital abnormalities.
- Down Syndrome (Trisomy 21)
- Edwards syndrome (trisomy 18)
As mentioned above, non-definitive tests that do not lead to a diagnosis, such as NIPT (non-invasive prenatal testing) , can be taken with almost no risk. On the other hand, if a non-definitive test is positive, a diagnosis can be obtained through definitive testing, which involves risk.
Let’s summarize non-definitive tests, including NIPT, once again.
| inconclusive test | ||
|---|---|---|
| NIPT (New Prenatal Diagnosis) |
Down syndrome (trisomy 21) Patau syndrome (trisomy 13) Edwards syndrome (trisomy 18) |
Since it only involves drawing blood, there is little risk. Performed after 9 weeks of pregnancy. |
| Ultrasonic examination | Evaluation of the presence or absence of serious congenital abnormalities including Down syndrome (trisomy 21) |
This test is also performed during prenatal checkups, and there are almost no risks. Evaluation of the possibility of congenital abnormalities in the fetus is performed around 11 to 13 weeks of pregnancy. During the 19th to 20th and 28th to 30th weeks of pregnancy, we will monitor growth, development, and whether there are any heart or bone diseases. |
| Maternal serum marker test | Down syndrome (trisomy 21) Edwards syndrome (trisomy 18) Neural tube defect (open neural tube malformation) |
Since it only involves drawing blood, there is little risk. Performed after 15 to 18 weeks of pregnancy. |
| Combined inspection |
Down syndrome (trisomy 21)
Trisomy 18 |
It is a test that combines ultrasound and blood sampling, and there is almost no risk. Performed around 11 to 13 weeks of pregnancy. |
Are there any risks to undergoing NIPT (new prenatal testing) at an uncertified facility?
In addition to certified facilities, there are also non-certified facilities where NIPT (new prenatal testing) can be performed.
Non-certified facilities are not illegal, and they have the advantage of being able to perform tests that certified facilities cannot. Certified facilities can only test for three diseases with NIPT: Down syndrome (trisomy 21) , Patau syndrome (trisomy 13) , and Edwards syndrome (trisomy 18) , but non-certified facilities can test for more detailed items, such as structural abnormalities such as numerical abnormalities of autosomes (chromosomes 1-22) and sex chromosomes, and deletions and duplications, depending on the facility.
In addition, you may be able to get the same test done at a cheaper price than at a certified facility.
Choose a testing facility that best suits your needs.
About Genetic Counseling
Genetic counselling involves providing evidence-based medical information to help people understand and deal with genetic diseases, worries and questions, as well as providing psychological and social support to help people solve their problems using medical techniques and information on their own.
The decision to undergo prenatal testing can often be difficult for you to make, and genetic counselling can often help you make that decision.
If you are unsure whether to take NIPT (new prenatal testing) , it may be a good idea to consult with a medical institution that provides genetic counseling.
summary
NIPT (New Prenatal Testing) is a test that can be performed early in pregnancy without putting any burden on the mother and child. At Hiro Clinic NIPT , in addition to the specified chromosomal abnormalities, we can also find out about the possibility of a wide range of congenital abnormalities.
Also, many people think about taking NIPT to feel reassured, but there is a possibility that they may receive a positive result instead of a negative one. At Hiro Clinic NIPT , we provide counseling and examinations after the test as follow-up in case the result is positive.
If you are considering NIPT, please feel free to contact us.
Article Editorial Supervisor
Dr Hiroshi Oka
NIPT specialist clinic, MD
Graduated from Keio University, School of Medicine
