🧬Diagnóstico del Síndrome de Down en el embarazo ¿Qué pruebas hay que realizar? 🫃

👉When we talk about chromosomal abnormalities, we very often refer to Down syndrome (trisomy 21, meaning there are three chromosomes instead of two in pair 21), as it is the most common (one in every 750 live births), with its prevalence increasing with maternal age. It is the most well-known, but it is not the only one, as other chromosomal abnormalities that can also occur include trisomy 13 and trisomy 18. Prenatal Screening for Down Syndrome The most effective screening test for chromosomal abnormalities will be the one that identifies fetuses at high risk of having a chromosomal problem with the fewest possible false positives. Currently, the combination of maternal age, biochemical data (β-HCG and PAPP-A) obtained from a maternal blood test, and data from the 12-week ultrasound (nuchal translucency) allows for a Down syndrome detection rate of between 85% and 95%, with a false-positive rate of only 5%. This detection rate is much higher than that obtained using only maternal age data (30%) or blood tests alone (60%). The risk assessment for the main chromosomal abnormalities performed in the first trimester of pregnancy (Combined Risk Index) is an effective, efficient, and cost-efficient tool. Although many centers perform both the blood test and the ultrasound simultaneously on the same day (coinciding with the 12-week ultrasound), the best results are obtained when the blood test is performed between weeks 9 and 10, and the ultrasound at week 12. Non-invasive prenatal test In recent years, a test called the Non-invasive Prenatal Test (NIPT) has emerged. Advances in genetic studies now allow for the analysis of certain fetal chromosomes in placental cells present in the mother's blood. Its detection rate for Down syndrome is over 99%, with false positives decreasing to 0.1%. 👉 www.egom.es/cita-previa The chromosomes of placental cells and the fetus match in 99.5% of cases. Its detection rate for Down syndrome is over 99%, with false positives decreasing to 0.1%. Even with these figures, it remains a method for detecting risk, and positive cases require confirmation through chorionic villus sampling (CVS) or amniocentesis. At EGOM, we have a Prenatal Diagnostic Unit that meticulously performs the essential ultrasounds for monitoring pregnancy. In this case, we perform the 12-week ultrasound, also known as the "genetic ultrasound," an indispensable tool for studying the risk of major chromosomal abnormalities. We also offer pregnant women the option of performing diagnostic tests for chromosomal problems (CVS or amniocentesis) when a high risk is detected in screening tests.