Pediatrics & Pediatric Care

Chromosomal defect affects around 0.4% pregnancies. To the most common chromosomal abnormalities belongs Down syndrome (0.2%), then trisomy 18, 13 and sex chromosome abnormalities. The only available prenatal diagnostic test for chromosomal defects is invasive testing, CVS (chorionic villus sampling), amniocentesis or cordocentesis. As these invasive methods are connected with about 0.5% of miscarriage, they are recommended only pregnant women having high risk of fetal chromosomal abnormality. Thus, all pregnant ladies are offered only safe screening tests, which estimate the risk of chromosomal defects. If the risk is high (more than 1:300, means 0.3%) an option of invasive testing is being discussed with pregnant lady. The most accurate screening test at this moment represents NIPT (non-invasive prenatal testing) methods, which analyses fetal DNA in maternal blood. These tests are expensive, therefore only some group of pregnant ladies decide for this testing. Most common and second most effective screening for chromosomal defects represents first trimester screening. The older screening methods like maternal age alone or second trimester biochemistry (triple or quadruple test) are considered to be much less accurate thus are not recommended. This presentation describes current available options of screening for chromosomal defects and explains their advantages and disadvantages.