Yhdistelmäseulonta

Yhdistelmäseulonta, often translated as combined screening or integrated screening, is a prenatal diagnostic method used to assess the risk of a pregnant woman carrying a fetus with certain chromosomal abnormalities. It combines information from several different tests to provide a more accurate risk assessment than any single test alone. Typically, this involves an ultrasound examination performed early in pregnancy, usually between the 11th and 14th week of gestation, and a blood test analyzing specific maternal serum markers.

The ultrasound component of yhdistelmäseulonta focuses on measuring the nuchal translucency, which is the fluid-filled space at the back of the fetal neck. An increased nuchal translucency measurement can be associated with a higher risk of chromosomal conditions like Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13). The blood test measures the levels of certain pregnancy-associated hormones and proteins, such as PAPP-A (pregnancy-associated plasma protein-A) and free beta-hCG (human chorionic gonadotropin).

By integrating the data from the nuchal translucency measurement, maternal age, and the biochemical markers from the blood test, a personalized risk score for the fetus is calculated. This combined approach offers a higher detection rate and a lower false-positive rate compared to older screening methods that relied on single tests. It is important to note that yhdistelmäseulonta is a screening test, not a diagnostic test. A high-risk result does not definitively mean the fetus has a chromosomal abnormality, but rather indicates an increased likelihood. Further diagnostic procedures, such as chorionic villus sampling (CVS) or amniocentesis, would be offered to confirm or rule out a diagnosis.