Science and medicine have developed in recent years in the area of pregnancy, maternal and fetal health.
In addition to tests that are considered old and safe, new tests based on new technologies have also been added, and some of them have even enabled high levels of accuracy that were not in the past.
This progress allows families expecting a baby to experience pregnancy more quietly when decisions about its continuation and information about its health arrive more quickly and more surely.
The following article focuses on the important tests to help pregnant couples understand and know what is recommended to pass the day in pregnancy tests.
There are three types of expanded tests in pregnancy:
- Survey pregnancy tests – routine tests and expanded tests
- Invasive diagnostic tests
- Non-invasive DNA testing (NIPT)
Genetic screening tests of pregnant women for hereditary diseases
This is one of the most dramatic medical developments.
The purpose of the genetic screening tests is to locate carriers of hereditary genetic diseases in order to prevent the birth of children with these diseases.
There is a range of routine tests conducted by the HMO, in which up to 20 common syndromes can be reviewed according to the origin of both partners.
In addition, there is an expanded, advanced genetic survey tests : Family Genetix.
This is a test carried out using Next Generation Sequencing (NGS) genetic engineering technology, which also examines the common and familiar mutations in the same population as the other tests,
And expands the screening and mapping of rare mutations.
Familygentics scans over 200 different syndromes and genetic diseases. The test is considered a highly expanded genetic screening test.
Genetic screening is recommended for every couple who plans a pregnancy, even if it is not their first pregnancy.
The test is performed by a simple blood test or a saliva sample at many medical centers around the country.
Screening tests for Down syndrome in pregnancy:
In addition to the genetic screening tests carried out for the couple in most cases before or during pregnancy, there are screening tests (covered by the health funds) during pregnancy, aimed at detecting chromosomal disorders in the fetus itself.
The routine screening tests have an ability to identify Down syndrome that is about 90% accurate.
These are basic tests, the basis for which is only statistical, so that many normal children are born even though routine screening tests showed a risk outcome.
Therefore, the medical recommendations are that when a screening of the screening tests is found to be unusual, the woman will be referred for a diagnostic test to confirm or deny the finding.
First trimester screening – first trimester for pregnancy
This is a statistical calculation in which the woman’s age is weighted with an ultrasound result and a blood test (PAPP-A and Free β-hCG).
This test is performed between 10-14 weeks of pregnancy. When the test results indicate an increased risk, the woman will be referred for a diagnostic test of amniotic fluid or chorionic villus to confirm or deny the finding.
Second trimester screening – second trimester of pregnancy (triple test, “fetal protein”)
In this test, the result weighs the levels of 3 proteins in the mother’s blood: the fetal protein level (AFP), the level of the thyroid hormone (HCG), and the estroliol level (UE3).
The blood test is performed between 16-20 weeks of pregnancy.
When the test results indicate an increased risk, the woman will be directed to perform a diagnostic test of amniotic fluid to confirm or deny the finding.
In addition, the level of the fetal protein itself is a screening test for an open defect in the fetus (in the lining of the abdomen or in the nervous system).
Invasive diagnostic tests in pregnancy:
Invasive tests. It is recommended that they be performed for the most part, when a high risk of fetal syndrome is identified, or if genetic mutations are found in the parents.
The purpose of diagnostic tests is to confirm or rule out syndromes and pathological findings at high levels of certainty.
Amniocentesis test in pregnancy
Reliable and familiar testing performed by ultrasound guidance.
During the test, amniotic fluid is pumped to make an accurate genetic diagnosis of the fetus.
The examination is done by inserting a needle through the abdominal wall, and in most cases it is a safe procedure.
Along with high reliability in the test results, there is still a low risk of miscarriage as a result of the test or infection that can lead to premature termination of pregnancy.
After the test it is recommended to rest for about 48 hours.
The test takes place between weeks 16 and 20 and in most cases the results come about 3 weeks later.
In this test, we diagnose:
- A chromosome test – the test that detects, among other things, Down Syndrome, by diagnosing a surplus in the chromosome 21.
- Embryonic protein – If a blood test has a high protein level, it is recommended to check for amniotic fluid.
- The genetic chip test (CMA) – a new relative test that did not exist in the past and is now gaining popularity. Its purpose is to identify the exclusion of tiny DNA fragments (changes called sub-microscopes).
These changes may be the cause of a large number of genetic syndromes accompanied by birth defects, developmental and mental disorders and some cases of autism.
When signs of abnormalities were detected in the ultrasound at earlier stages or when the peripheral transparency is more than 3 mm, the test will be funded by the Ministry of Health.
In other cases it can even be done privately.
There are institutes in Israel where the test is performed as an alternative to the stereotype. In 3-4% of the cases, findings are obtained whose meaning is unclear.
Genetic testing in pregnancy
Following the results of the tests on the carrier of genetic disease in the couple found during the genetic screening test (such as cystic fibrosis), usually prior to or at the beginning of the pregnancy, the fetus will be tested for the disease, and this will be done only if findings are found in the test results.
Fecal colic test in pregnancy
The purpose of the test is to extract a sample of the placenta from the placenta to rule out or confirm syndromes such as Down Syndrome, etc., or following a genetic carrier of a disease in the couple.
The test can be performed between weeks 10-13 with a certain risk of miscarriage, which is about 1%.
The test is considered invasive and is performed by inserting a plastic tube through the vagina (sometimes there is also an option to insert the tube through the abdominal wall, depending on the location of the placenta).
The genetic tests performed on the placenta are the same as those performed with amniocentesis (see above).
Non-invasive NIPT DNA testing in pregnancy
This is a relatively new test for pregnancy tests that have been reviewed so far. The uniqueness of the test is its simplicity, accuracy and high safety.
Until her arrival, it was possible to diagnose common syndromes only in the amniotic fluid test.
Now, the NIPT test can identify common syndromes at a very high level of accuracy, safely without the risk of miscarriage and very early in pregnancy, since the test is performed with a simple blood test starting from the 10th week of pregnancy.
The New England Journal of Medicine (NEJM) published a study that found that NIPT and Teva’s NIPT test reduces 89% of amniocentesis if NIPT is performed as an initial screening test for all pregnant women.
Starting from the 10th week of pregnancy, the mother’s blood contains DNA fragments (genetic material) originating in the embryo. Therefore, in the blood test of the mother, it is possible to examine the ratio between the number of DNA segments from each chromosome, thus identifying a state of excess / missing segments from a particular chromosome.
Although NIPT and RIP have high rates of accuracy (99.9% for Down syndrome) and high percentages of accuracy for other common syndromes, as many studies have shown, the test is still defined as a screening rather than a diagnostic test.
Therefore, when the test indicates an abnormal result, ie an increased risk of one of the syndromes being tested,
The recommendation is to be confirmed or denied by a diagnostic test (cystic fibrosis or amniocentesis).
When there is no result at all, what is commonly referred to as a “technical failure,” the recommendation will also be to perform a diagnostic test.
The NIPT test can be found at:
Down Syndrome – According to studies, a natural test of nature diagnoses a 99% certainty of Down Syndrome
Triple Syndrome X
Verifi Plus which is an extended and extended test also locates:
A small number of syndromes examined in the genetic chip (CMA)
Abnormalities in other chromosomes
In conclusion, despite the uncertainty, and the excitement brought by pregnancy, there are quite a few pregnancy tests throughout its length and even pre-pregnancy stage.
In order to obtain a sense of security it is recommended that you perform the correct tests at the appropriate time in order to make decisions regarding the continued follow-up of the pregnancy as early as possible. It is advisable to consult with the women’s doctor who accompanies the pregnancy and geneticists in order to undergo a quiet and healthy pregnancy.