3 tests to be done during pregnancy
“Prenatal screening tests”, popularly known as intelligence tests, are of great importance for the future lives of children and families.
Screening tests, known as double, triple and quadruple tests, can be applied to expectant mothers during the weeks recommended by the doctor during pregnancy.
With today’s technology, although the intelligence level of the baby in the mother’s womb has not been evaluated yet, these three tests remain important in determining the risk of diseases that may cause mental retardation in the baby. From Memorial Kayseri Hospital Gynecology and Obstetrics Department, Op. Dr. Nilgün Avşar Zengin gave information about the screening tests during pregnancy.
Dual test at 11-14 weeks of pregnancy
With double, triple and quadruple tests, it is possible to screen for some of the diseases that can cause mental retardation. These are “prenatal screening tests” or “down syndrome” screening tests.
Even if the results are at a normal level, there may be a risk of mental retardation due to another disease in the baby. The tests reveal a result in terms of the high risk factor. The double test is done between 11-14 weeks of pregnancy. In ultrasound, the baby’s head-rump distance measurement (CRL) is applied when it is between 38-84 millimeters.
Triple and quadruple tests at 16-20 weeks of pregnancy
Triple and quadruple tests are performed in the second trimester of pregnancy (week 16-20). The triple test, which is done to know the anomalies that may occur in the baby during pregnancy, is important in terms of determining whether there is a risk of trisomy 21 (down syndrome) and trisomy 18 (edwards syndrome) in the baby, as in the double test. As a result of the quadruple test, the rate of detecting whether babies have Down syndrome before they are born is 80%. However, tests cannot definitively determine whether these syndromes are present in the baby.
Definitive diagnosis is made by CVS or amniocentesis. In addition to the B-hCG and free estriol (uE3) and AFP levels evaluated in the blood taken from the mother in the triple test, the addition of Inhibin-A level in the quadruple test to the formula increases the success of the test.
Integrated testing for Down Syndrome
Integrated tests are also applied by performing two tests sequentially during pregnancy. Between the 11th and 14th weeks of pregnancy, PAPP-A is measured in the mother’s blood and the nuchal translucency (NT) of the baby is measured. In addition, NT and PAPP-A or NT, PAPP-A and B-HCG are also examined between these weeks. After the quadruple test performed between the 16th and 20th weeks, the baby’s neck and PAPP-A measurement are integrated and the risk factor is determined. The integrated test is the most successful test in detecting babies with Down syndrome during pregnancy. 92% of babies with Down syndrome are identified by the fully integrated test.
High risk if the directory is corrupt
If, as a result of the screening tests, the risk of the baby in the mother’s womb having Down’s or Edwards’ syndrome is high, sample tissue is taken from the placenta (chorionic villus) with a fine needle between the 10th and 13th weeks of pregnancy. The purpose of the procedure known as Chorionic Villus Biopsy (CVS), which is done without anesthesia, is to have information about the genetic structure of the baby. The chorion layer that develops from the embryo is the same as the genetic structure of the baby. Thanks to the tissue taken, the chromosome index is obtained and genetic diagnosis can be made. If there are defects in the chromosome sequence, the baby has a high risk for these syndromes.
Medimagazin, 3 tests to be done during pregnancy, 2018