We use screening tests to diagnose some chromosomal anomalies (the most well-known being Down syndrome) and structural disorders during pregnancy follow-up. Screening tests us; It shows which risk group the patient is in and helps us identify patients who should be referred to the next step, diagnostic tests. In other words, screening tests do not give results such as whether there is an anomaly or not. However, definitive results can be reached with diagnostic tests. Double, triple, quadruple tests and fetal DNA test (NIPT) are used as screening tests, while amniocentesis and chorionic villus sampling (CVS) are applied as diagnostic tests.
SCREENING TESTS
Double screening test: It is performed between weeks 11 and 14. Maternal age, biochemical markers (checked in blood) and ultrasonographic markers (nuchal translucency of the fetus (nt) and presence or absence of nasal bone) are analyzed.
Triple and quadruple screening test: It is performed between the 15th and 20th weeks. The difference between them is that another biochemical marker has been added to the quadruple test. Again, maternal age and fetus measurement are also included in the calculation.
NIPT test: DNA analysis is performed by separating the cells of the fetus in the sample taken from the mother's blood.
DIAGNOSIS TESTS
Chorion. villus sampling (CVS): 9-14. A sample is taken from the fetus's placenta by inserting a thin needle into the mother's abdomen or cervix between weeks 15 and 15.
Amniocentesis: It is performed after the 15th week. Again, with a thin needle, a sample is taken from the fluid in the fetus (amniotic fluid) by entering the mother's womb under ultrasound guidance.
Cordocentesis: Blood is taken from the baby's umbilical cord and examined. Nowadays, it is mostly used to donate blood to babies with anemia due to blood incompatibility.
If they are in the risk group in screening tests, diagnostic tests should be started. In such cases, expectant mothers rightfully experience anxiety.
Of course, no pregnant woman is obliged to undergo either screening or diagnostic tests. We are obliged to inform. Pregnant women should decide, together with their husbands, whether a screening test will be performed or not, and if so, which test will be performed. Sometimes, there may be people who do not want a screening test but want to have a direct diagnostic test. After detailed information, the decision should be left to the family.
I wish you healthy and happy days.
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