Prenatal diagnostics

Is my baby doing well? This thought is probably shared by almost all expectant parents throughout the nine months. Various examinations in so-called prenatal diagnostics promise an answer to this question. But what can the tests achieve, and how useful are they?

What is prenatal diagnosis?

In principle, any form of prenatal care during pregnancy, including the scheduled prenatal and ultrasound examinations, provides information about the child's development, possible abnormalities or irregularities, and can therefore be understood as a form of prenatal diagnostics. Generally, the term prenatal diagnostics (PND) encompasses various special examinations and tests In summary, these are performed by qualified doctors during pregnancy and allow statements about the probabilities of certain malformations, hereditary diseases, and chromosomal abnormalities of the fetus. Prenatal diagnostics are used, for example, when the risk of a particular disease is increased. However, their results are not always conclusive and cannot diagnose all disorders of the child.

What prenatal examinations are available?

Prenatal diagnostics include various examinations: non-invasive (those that do not penetrate the body), as well as invasive (which require an intervention). All traditionally understood prenatal examinations go beyond the and are only performed if the risk of potential diseases or disabilities is increased and/or if the pregnant woman explicitly requests the examinations.

Non-invasive methods

Non-invasive prenatal diagnostics include ultrasound and blood tests:

• Fetal diagnostics: The unborn - in addition to the three scheduled ultrasound examinations - is examined with a high-resolution ultrasound device by specially trained doctors, for example in a prenatal center. Particular attention is paid to the organs, the development of the limbs, and the blood vessels. During detailed diagnostics, certain diseases, such as heart defects, can be detected. Likewise, specific physical features can indicate other illnesses – however, additional tests are usually necessary for an accurate diagnosis.

• Blood test (NIPD): The non-invasive prenatal test refers to a blood test that can be performed as early as 11th week of pregnancy can be performed. About 20 milliliters of blood are drawn from the pregnant woman, which already contains the child's DNA at this stage. In the laboratory, the child's chromosomes are compared with those of the mother and their ratio is determined. A corresponding discrepancy can indicate trisomy 13, 18, 21, monosomies, or deviations in sex hormones. The non-invasive examination offers very high accuracy when it comes to ruling out chromosomal disorders.

• First Trimester Screening (FTS): The first trimester screening is offered directly on-site by many gynecological practices. It consists of an ultrasound examination with nuchal translucency measurement and a blood test, which checks the concentration of the pregnancy hormone HCG and the pregnancy-specific protein PAPP-A. Changes in these values can indicate a trisomy. The nuchal translucency measurement can also indicate a chromosomal disorder or a heart defect. It is performed between the 11th and 13th week of pregnancy checked by ultrasound whether there is an accumulation of fluid under the skin of the fetus's neck, which appears as a dark line on the ultrasound. Based on the blood values, the nuchal translucency measured by ultrasound, and the age of the pregnant woman, the individual risk of a chromosomal abnormality is finally calculated using a special mathematical formula. If the risk exceeds 1:200, the pregnant woman is usually advised to consider further examinations; only then can the suspicion of an actual chromosomal disorder be confirmed. Specific blood flow patterns or the length of the fetal nasal bone are not included in the calculation, but they can also provide early indications of chromosomal or organic developmental disorders and thus further reinforce the suspicion when an abnormal nuchal translucency is detected.

• Organ screening (second trimester screening): The special organ screening takes place between the beginning of the 19th and the end of the 21st week of pregnancy , also parallel to the second scheduled ultrasound, takes place. As the name suggests, in a specialized practice, all organs, as well as the face, back, chest, diaphragm, abdominal wall, and extremities of the fetus are examined in detail. This examination offers an additional opportunity for prenatal assessment, especially for high-risk pregnancies.

Invasive methods

Invasive examinations are those that involve a minor intervention into the pregnant woman's body.

• Chorionic villus sampling/Chorion biopsy (placental puncture): In this procedure, cells from the unborn baby are either obtained using a thin hollow needle through a puncture in the abdominal wall or with a catheter through the vagina from the placenta. The position of the baby is precisely determined beforehand by ultrasound and monitored throughout the entire procedure to avoid any harm. The chorionic villus sampling is performed from the 12th week of pregnancy possible and enables very accurate exclusion diagnoses regarding chromosomal abnormalities such as Trisomy 13, 18, and 21, as well as hereditary diseases of the unborn child. The examination can be useful if the pregnant woman has already given birth to a child with a hereditary disease or chromosomal disorder, if familial genetic defects are known, if the ultrasound examination was abnormal, or if the risk is considered elevated due to the mother's age. The result of the examination offers nearly 100% certainty. The risk of placental rupture or infection from invasive procedures is between 0.5 and 1% — this should be explained to you by the medical expert before the procedure, along with the effectiveness and reliability of the diagnostic method.

• Amniocentesis (amniotic fluid test): The examination of the amniotic fluid is from the 15th week onwards, or 16th week of pregnancy , but also later on. In this procedure, a thin hollow needle is inserted through a small puncture in the abdominal wall to extract a few milliliters of amniotic fluid from the amniotic sac, which also contains cells from the unborn baby. Before and during the entire procedure, the position of the baby and the course of the needle are carefully monitored using ultrasound. The subsequent laboratory analysis of the amniotic fluid can detect trisomies 13, 18, or 21, as well as neural tube defects and inherited diseases such as metabolic disorders or skeletal diseases. The test is particularly appropriate when the risk of chromosomal or genetic abnormalities is increased, for example after an abnormal nuchal translucency measurement, with a family history, or if the risk is elevated due to the mother's age. If a chromosomal abnormality is detected during the test, the accuracy is nearly 100%. In very rare cases, amniocentesis can lead to premature rupture of membranes (in 0.5 to 1% of cases).

• Cordozentese (Umbilical Cord Blood Sampling): An umbilical cord puncture is possible from the 12th week of pregnancy, but more significant from the Week 18 of pregnancy . During the examination, a blood sample containing fetal cells is obtained through a thin hollow needle inserted via a puncture in the abdominal wall. umbilical cord taken. During the subsequent examination, conditions such as anemia, infections, metabolic disorders, hydrops fetalis (fluid accumulation in the fetal body), as well as chromosomal abnormalities and certain hereditary diseases can be diagnosed. Some of these conditions can already be treated during pregnancy by administering medications, hormones, or a blood transfusion into the child's body via the umbilical cord. This is referred to as prenatal invasive therapy. The Risk of miscarriage occurs in 1 to 3 % after umbilical cord puncture; in rare cases, it can also lead to uterine contractions, membrane rupture, infections, preterm labor, or a nuchal cord hematoma.

Even though the sample collection with a needle initially sounds intimidating, all invasive methods are pain-free for the child and are also perceived as largely pain-free by most pregnant women. They are performed on an outpatient basis, but you should definitely rest for several days after each examination. Usually, an ultrasound examination is also performed the day after the procedure to ensure that your baby is active and that the amniotic fluid volume is sufficient.

What can prenatal diagnostics do? Risks and criticism

Topics related to prenatal diagnostics are often discussed very emotionally, and there are both proponents and critics of prenatal examinations.

Many expectant parents hope to gain information about whether they are expecting a healthy child through prenatal examinations. However, critics argue that ultimately cannot guarantee an examination that a child will actually be born healthy : Only a part of all possible impairments can be detected during pregnancy, and the majority of disabilities are only caused by complications during pregnancy, childbirth, or throughout life. Additionally, all tests can result in false diagnoses as well as overlook conditions, and invasive examinations may carry risks.

At the same time, invasive diagnostics performed by experienced and specialized doctors enable the confirmation or exclusion of suspected diagnoses with nearly one hundred percent certainty. An unremarkable result can reassure expectant parents, for example, if they have already experienced a miscarriage or if hereditary pre-existing conditions are known in the family. Equally important is the fact that some conditions can now be treated in the womb thanks to modern medicine. Furthermore, early knowledge can assist expectant parents in their (mental) Preparation help with life with a sick child and the further course of the pregnancy can be closely monitored, and children with certain disabilities or illnesses of the Start into life made easier are planned, for example, by scheduling the birth in a specialized clinic.

Guidelines for Prenatal Diagnosis

If an abnormal finding occurs during regular preventive examinations, your doctor is generally obliged to inform you (and your partner). However, you have the right not to know – meaning you can decide not to pursue the finding further through prenatal examinations. Very important: It will do not conduct a prenatal examination without your prior written consent carried out and you can withdraw your consent at any time before the examination. Your doctor is also obliged to inform you comprehensively before each prenatal examination, to explain possible risks and consequences, and to inform you of your right to free consultation by the pregnancy counseling center to point out. This is important to fully understand in advance what a possible diagnosis means. Your doctor must also inform you beforehand about the risks associated with each examination.

How much does prenatal diagnostics cost?

Specialized testing procedures and invasive procedures as part of targeted prenatal diagnostics are generally not included in the planned statutory health screenings during pregnancy. Therefore, their costs are not typically covered by health insurance. However, if abnormalities are detected during routine check-ups or if hereditary pre-existing conditions are present in your family, the costs for the respective examinations are usually covered by health insurance. It is best to inquire directly with your health insurance provider about this. Since the risk of chromosomal abnormalities increases with age, all pregnant women over 35 are also entitled to invasive diagnostics. Even without medical indication, many gynecological practices offer prenatal diagnostics as so-called individual health services (IGeL). In this case, you will have to cover the costs of the examinations yourself.

There are few topics as controversial as prenatal diagnostics and how to handle it. Whether the examinations are a curse or a blessing, bring relief or uncertainty, is very individual, and the decision for or against them is one that all expectant parents should make for themselves. No matter how you feel about it: Never let yourself be pressured into something you feel uncomfortable with, and exercise your right to information and support if you wish. You can find counseling centers in many cities, for example at , or through your gynecologist.