The Association between Serum Biochemical Markers and Early Amniocentesis in Diagnosing Chromosomal Anomalies: A...

Efforts to improve prenatal diagnosis of Down syndrome have been made, with amniocentesis representing an invasive procedure, and maternal serum biochemical markers are among the non-invasive options. This study aimed to examine the association between serum biochemical marker values and amniocentesis results in the prenatal diagnostics of Down syndrome in early pregnancy.

In a cross-sectional study, data from pregnant women in the first trimester undergoing amniocentesis test for the diagnosis of fetal genetic diseases were collected during 2021-2022. Maternal weight, maternal age, gestational age at nuchal translucency (NT) scan, nasal bone (NB) status, and serum chemical biomarkers-including pregnancy-associated plasma protein-A (PAPP-A), and beta-human chorionic gonadotropins (β-hCG) were assessed.

Of 1,987 amniocentesis cases, 96.5% were normal, and 3.5% were abnormal. Down syndrome was present in approximately 3% of cases. Maternal weight was significantly lower in the abnormal amniocentesis group than in the normal group. After adjusting for maternal weight, maternal age, NT, and β-hCG were significantly higher in the abnormal amniocentesis group, whereas PAPP-A was lower. The NB status did not differ between groups. A PAPP-A level of <0.42 multiple of median (MoM) (sensitivity=90%, specificity=68%) and a β-hCG level of ≥1.52 MoM (sensitivity=76%, specificity=70%) acceptably predicted Down syndrome in abnormal amniocentesis cases. Among the 69 abnormal amniocentesis cases, 49 cases had Down syndrome; of these, 75.5% had a Down syndrome risk of ≤1:100.

Both β-hCG and PAPP-A had independent diagnostic value in predicting Down syndrome in early pregnancy. It is recommended that a Down syndrome risk of up to 1:100 warrant direct amniocentesis, while cases with a risk greater than 1:100 should be offered non-invasive alternatives.