Introduction: Down syndrome (DS), caused by trisomy 21, is a common chromosomal abnormality associated with intellectual disability, developmental delays, and characteristic physical features. Prenatal screening enables early risk assessment and informed decision-making. Advanced maternal age is a major risk factor, highlighting the need to consider maternal age alongside biochemical and ultrasound markers. This study investigated the association between maternal age and key prenatal markers—including Pregnancy-Associated Plasma Protein A (PAPP-A), β-human Chorionic Gonadotropin (β-hCG), AlphaFetoprotein (AFP), Inhibin A, unconjugated Estriol (uE3), and Nuchal Translucency (NT)—and evaluated their contribution to Down syndrome risk stratification across maternal age groups.
Methods: A cross-sectional study was conducted on 138 pregnant women referred to a diagnostic laboratory in Anar County, Kerman Province. Serum markers were measured in first- and second-trimester screenings, alongside ultrasound assessment of NT. Statistical analyses, including one-way ANOVA, examined associations between maternal age, markers, NT, and estimated Down syndrome risk.
Results: Maternal age was significantly associated with estimated Down syndrome risk, highest among women aged 40–45 years and lowest in those aged 20–25 years. AFP and uE3 demonstrated the strongest predictive associations with risk, whereas PAPP-A, β-hCG, and NT contributed less prominently.
Conclusion: Combined prenatal screening using maternal serum markers and NT improves early identification of pregnancies at increased risk for Down syndrome. Integrating maternal age with biochemical screening optimizes risk stratification, especial ly in regional programs. Further multicenter studies are recommended to confirm and expand these findings .