Which screening test is recommended in the first trimester for detecting fetal aneuploidy?

The recommended screening test during the first trimester for detecting fetal aneuploidy is the combination of pregnancy-associated plasma protein A (PAPP-A), beta-human chorionic gonadotropin (beta-hCG), and an ultrasound to measure nuchal translucency. This screening approach is effective because it assesses multiple markers that can indicate the risk of chromosomal abnormalities, such as Down syndrome (trisomy 21) and trisomy 18.

PAPP-A is a protein produced by the placenta that can reflect placental health and fetal well-being, whereas beta-hCG is a hormone that also varies in levels in certain aneuploid conditions. The nuchal translucency, which measures the fluid at the back of the fetal neck through ultrasound, can correlate with the risk of congenital heart defects and chromosomal abnormalities. Collectively, this non-invasive screening approach is typically offered between 11 and 14 weeks of gestation, allowing for early risk assessment and informed decision-making for potential diagnostic testing as necessary.

While amniocentesis is a diagnostic procedure that can definitively determine genetic conditions, it is not performed in the first trimester and carries a risk of complications. Maternal serum alpha-fetoprotein (MSAFP), along