Prenatal testing in pregnancy – what do you need to know?

Prenatal testing – what does it look like and what is it?

Prenatal testing in pregnancy is performed to diagnose or exclude the existence of fetal malformations, at the stage of pregnancy, even before birth. Thanks to prenatal testing, parents-to-be can rest assured about their baby’s health and life after birth. They are also able to prepare for an offspring that will require specialized care.

Prenatal testing during pregnancy is not mandatory, but recommended. Moms who are over 35 years of age should especially opt for them, as the risk of fetal defects increases with age. Prenatal testing is also recommended for women who have given birth to a sick child or have a positive family history. It means that relatives have been diagnosed with metabolic or genetic diseases. It is worth remembering that such mothers have an increased risk of having a sick child again, so prenatal testing is especially important in their case. Anyway, they are also helpful in diagnosing diseases of the nervous system, heart and spine.

Modern medicine makes it possible to conduct prenatal tests by the most diverse methods. They are divided into non-invasive and invasive. The former are performed without violating the skin. The second is more advanced, as the material for the test is taken through the woman’s abdomen. Prenatal testing also uses a variety of tests, ultrasound and the mother’s blood, from which the baby’s DNA can be isolated.

When to do prenatal testing?

The timing of prenatal tests is determined by the pregnancy calendar. They should not be overlooked or forgotten, as there is no way to approach them at other stages of pregnancy. The first prenatal tests are possible from the 9th week of pregnancy. The patient is then given a blood screening test, which can determine both the course of the pregnancy and the sex of the baby. The test is non-invasive and completely safe.

Other non-invasive tests, such as genetic ultrasound, are performed from the 10th week of pregnancy. The best date is week 11-13 and should not be exceeded. A test that is performed on a similar date is a double test, called the PAPP-A test. If the results of this test are worrisome, the test is repeated after the 19th week. Between 14 and 21 weeks of pregnancy, on the other hand, a triple test is performed. It involves drawing the mother’s blood and analyzing it for concentrations of the pregnancy hormone beta-HCG.

The calendar for invasive prenatal testing presents itself similarly to the test dates. Between 15 and 20 weeks, an amniocentesis can be performed, which used to be one of the primary diagnostic tests for identifying potential fetal defects. It was also considered highly risky, although that view has now changed. Currently, amniocentesis is performed as early as 13 weeks of pregnancy, and the risk of complications is low (0.5%).

Another invasive prenatal test is a chorionic villus biopsy (CVS), a procedure performed through the abdominal shell or cervix between 11 and 14 weeks of pregnancy. Cordocentesis, which requires puncturing the umbilical cord and collecting material in the form of cord blood, is also invasive. This test can be performed after the 20th week.

What does prenatal testing look like?

No special preparations are needed for prenatal tests if they are not invasive and do not require anesthesia. Most tests are conducted from the mother’s blood, and the results are available within a few weeks. Tests such as ultrasound are performed through the abdominal shell of the pregnant woman and are completely painless for her. Invasive prenatal tests, where anesthesia is administered, can be inconvenient, as the pregnant woman may experience abdominal discomfort afterwards. 

When is prenatal testing especially recommended?

Prenatal tests can be performed by any pregnant woman, but they are especially recommended when:

• a woman has reached the age of 35, because then the risk of the child developing malformations, hemolytic and metabolic disorders, and diseases with a genetic basis increases;
• a woman became pregnant with a partner much older than herself, especially a man over 55;
• genetically determined diseases have been diagnosed in the mother’s or father’s family;
• The couple underwent an in vitro fertilization procedure;
• the pregnant woman has already given birth to a sick child, which significantly increases the risk of giving birth to another sick offspring.

It is worth remembering that prenatal diagnosis is used to assess the health of the fetus and mother. A pregnancy with a high risk of giving birth to a sick baby can endanger a woman’s life.

Non-invasive prenatal blood tests and more

Most often, non-invasive prenatal testing consists of screening tests. They are:

• PANORAMA test – allows you to determine the health of the fetus and its sex. It is conducted from the mother’s blood at 9 weeks of pregnancy;
• IONA test – is used to assess the risk of fetal malformations (Down, Edwards and Patau syndromes) during early pregnancy. It is conducted from the mother’s blood between 10 and 34 weeks of pregnancy. It is especially recommended for women over 35, those living with an older partner, and pregnant women who are in vitro fertilized;
• NIFTY test – confirms or rules out trisomy in the fetus. It is conducted from the mother’s blood, as this is the only way to isolate the baby’s DNA;
• PAPP-A (double) test – this is performed from the mother’s blood, between 11 and 13 weeks of pregnancy. Its task is to determine the concentration of the so-called. free BETA-hcg and PAPP-A protein;
• Triple test – a test performed from the mother’s blood between 14 and 21 weeks of pregnancy. The collected material is used to determine chorionic gonadotropin (BETA-hcg), free estriol and AFP pregnancy protein.

Read also: Lymphocytes in pregnancy – what is the norm? What if they are downgraded?

Non-invasive prenatal tests are also fetal echocardiography, which allows assessment of the fetal heart and cardiovascular system, and genetic ultrasonography. During the ultrasound, all organs, neck folds and bones of the fetus are measured. The test is performed on high-sensitivity equipment with special approvals. How long does a prenatal test with ultrasound take? Even an hour, because it is very precise.

Invasive prenatal testing

A woman is referred for invasive prenatal testing when screening tests have given questionable results and there is a high risk of fetal malformations. Such pregnant women usually undergo amniocentesis, a test performed with a violation of the mother’s abdominal layers. During the procedure, a sample of amniotic fluid is taken and then tissue culture is conducted. Thanks to it, it is possible to determine the karyotype of the child and thus exclude or confirm the existence of chromosomal defects in the child.

A chorionic villi biopsy is also an invasive prenatal test. Its fragment is taken under ultrasound guidance, through the anterior abdominal wall or cervix of the mother’s uterus. Fetal DNA is isolated from the material and the chromosome arrangement is determined. Cordocentesis is equally invasive. During the procedure, the doctor punctures the umbilical cord and draws blood from it for examination. The material makes it possible to assess the health of the fetus, including the exclusion of malformations and hemolytic disorders.

Invasive testing is not compulsory, but deciding to do it can be crucial for the child. If the results of the screening tests did not give a definite answer, and the baby may be sick, this increases its chances of being treated while still in fetal life. The tests also provide an answer as to whether the pregnancy poses a threat to the mother’s life.

See also: Pregnancy week by week – pregnancy calendar

Prenatal screening tests and ultrasound – price

Many parents-to-be wonder how much prenatal tests cost. They are not chargeable for every pregnant woman. Women over the age of 35 and those who have given birth to a child with a genetic defect can perform these tests under one of the National Health Fund’s programs. Pregnant women who do not meet these criteria will have to pay for them.

Prenatal testing prices are quite high. The cheapest are the double and triple tests, which usually cost no more than 250 zlotys. Much more expensive are invasive prenatal tests. You have to pay between 1,300 and 2,500 zlotys for them, depending on the type of test and the facility that performs it.

Why do prenatal tests and what do the results provide?

The results of screening tests and other prenatal tests have a reliability of 95%. If there is any doubt about the health of the baby and mother, the woman is referred for invasive tests. They make it possible to determine or exclude fetal disease with almost 100 percent certainty.

Although prenatal testing during pregnancy is not mandatory, it is worth doing. Thanks to them, parents can be reassured about the course of the pregnancy or prepare for the birth of a child requiring special care.