Is fetal genetic testing compulsory?

Non-invasive prenatal tests, above all the composite test, are recommended for every pregnant woman, regardless of her age, number of pregnancies, obstetric or family history.

Fetal genetic tests in the strict sense are only those tests that allow genes to be examined by molecular diagnostic and cytogenetic methods. However, they are not obligatory - they are optional. It is very important for parents to make an informed decision.

In the popular sense, genetic tests in addition to molecular diagnostics are also referred to as non-invasive tests. These are then all tests that can determine the risk or likelihood of an unborn child having certain genetic disorders or birth defects.

In some cases, a pregnant woman can get a referral for prenatal screening under the National Health Service.

Indications for prenatal diagnosis are:

mother's age over 35,
the occurrence of a chromosome aberration of the fetus or child in a previous pregnancy,
the occurrence of structural chromosome aberrations in the mother or father of the child,
genetic load running in the family,
an increased risk of having a child affected by a monogenetic or multifactorial condition,
abnormal results of previously performed pregnancy tests.

What prenatal tests might be recommended, especially if the woman is at risk?

Two groups of prenatal tests can be distinguished. The first includes non-invasive (screening) tests. They are performed as appropriate in each trimester of pregnancy. They do not interfere with the fetal environment and therefore do not involve a risk of miscarriage.

Non-invasive research:

a composite test, i.e. a first trimester ultrasound, performed between the 11th and 13th week of pregnancy, called 'genetic' with a simultaneous dual blood test (PAPP-A protein and beta hCG free subunit),
A 'midline' ultrasound, performed between the 18th and 22nd week of pregnancy,
Third trimester ultrasound, performed between 28 and 32 weeks of pregnancy,
free fetal DNA testing, i.e. genetic testing of the baby from the mother's blood.

Invasive prenatal testing that allows for genetic diagnosis:

amniocentesis, which involves taking a sample of amniotic fluid to diagnose possible fetal diseases, is mainly performed in the early second trimester of pregnancy, i.e. after the 15th week of pregnancy,
cordocentesis, which is the puncture of the umbilical cord and collection of a blood sample of the unborn child, performed after the 18th week of pregnancy, usually after the 22nd,
trophoblast biopsy (chorionic villi biopsy, CVS), a sampling of the pregnancy tissue that will later form the placenta - performed between 11 and 14 weeks of pregnancy.

If a woman is not referred to them, she can go for the tests herself, as long as she is concerned about the health of the baby - except for invasive tests, which are always referred by a doctor.

Non-invasive prenatal tests and their results

Non-invasive tests are mainly triple ultrasound examinations and genetic tests in pregnancy from blood, which help to assess the health of mother and child. If the first prenatal tests show abnormal results, i.e. an increased risk of genetic diseases or a defect in the foetus, the attending physician may suggest invasive diagnostics, i.e. amniocentesis, chorionic villus biopsy or cordocentesis.

Non-invasive tests in the first trimester of pregnancy

Composite test (combined test) consisting of simultaneous assessment of ultrasound and biochemical parameters, i.e. a 'genetic' ultrasound and a double test.
"Genetic" ultrasound - an accurate ultrasound examination that allows the fetus to be viewed and the development of the entire organism to be assessed. The specialist, who holds a special certificate from the FMF (Fetal Medicine Foundation) or a prenatal examination certificate from the PTGiP (Polish Society of Gynaecologists and Obstetricians) - so not every gynaecologist - carefully views the baby's organs, including the heart, brain and kidneys, as well as the structure of its face, trunk and limbs. The test helps to determine the baby's risk of Edwards', Turner's or Down's syndrome and birth defects (including hydrocephalus, some heart defects, anterior abdominal wall defects); it is usually performed in conjunction with a biochemical test - the double test.
PAPP-A double test - The test is usually performed between the 10th and 14th week of pregnancy and is based on an analysis of the mother's blood, in which the concentration of protein A and the free subunit beta-hCG are checked. These are markers of chromosomal abnormalities. Their too high or too low concentrations can be interpreted as a higher risk of Down's, Patau or Edwards syndrome. An alarming result may be an indication for next-generation blood tests or invasive diagnosis; usually performed together with a 'genetic' ultrasound, nowadays rarely performed and interpreted without an ultrasound.
Free fetal DNA testing (e.g. Harmony, SANCO, Panorama, NIFTY, NeoBona) - performed with a blood sample taken from the mother, currently the most modern test on the market, which makes it possible to detect the presence of Down syndrome and, to a slightly lesser extent, other trisomies (Edwards syndrome, Patau syndrome) with almost 99% sensitivity. Some of them also make it possible to assess the presence of Klinefelter's syndrome, Turner's syndrome or the so-called microdeletion syndromes - but with much less accuracy than Down's syndrome. Unfortunately, these tests are not reimbursed and their cost is in the region of PLN 2000-3000. Most of these tests can be carried out from as early as the 10th week of pregnancy and there is no upper limit for this test.

In the second trimester of pregnancy

a mid-term ultrasound is usually ordered - this allows an even more accurate assessment than a first trimester ultrasound of the possible presence of genetic syndromes or organ defects in the foetus - simply because the baby is already larger, it is easier to see any abnormalities.

Historically, a triple test was still performed, but due to the very low sensitivity and specificity of this test and the availability of better methods (such as free fetal DNA and ultrasound), this test is almost no longer performed.

Why is fetal genetic testing worthwhile?

Specialised, non-invasive genetic tests in pregnancy from the blood will allow you to find out much more about your baby's health than basic visits to the gynaecologist in charge of the pregnancy (which are of course also necessary), if he or she does not carry them out himself or herself. The free fetal DNA test as well as the combined test is also recommended for pregnant women who have achieved fertilisation through IVF, even if a pre-implantation diagnosis has been carried out.

Prenatal tests are not reimbursed in a large proportion of cases, but they are recommended for all pregnant women. Their results determine whether a woman will be referred for further non-invasive and invasive tests. They can also provide important information on how to manage the pregnancy and how to prepare a woman for childbirth.

Thanks to modern prenatal diagnosis, it is also possible to qualify children who are not yet born for treatment. In this way, they make a significant contribution to improving the psychological wellbeing of expectant parents.