Second-trimester maternal serum inhibin-A screening for fetal Down syndrome in Asian women

Case–control studies in the Caucasian population showed that maternal serum inhibin‐A is elevated in Down syndrome pregnancies and may be a useful second‐trimester marker in addition to human chorionic gonadotrophin (hCG) and alpha‐fetoprotein (AFP). Data in the Asian population are lacking. We measured inhibin‐A levels in the stored maternal sera of 49 Down syndrome pregnancies and 341 controls with a commercially available assay and expressed them as the multiples of the median of the gestational week. The log means and standard deviations for case and control inhibin‐A MOMs were 0.209, 0.226, and 0.002 and 0.177, respectively. Median inhibin‐A MOM in Down syndrome cases was elevated to 1.62 (95 per cent confidence interval, 1.29–1.82). 36 per cent of Down syndrome cases were expected to be detected at a 5 per cent false‐positive rate. However, inhibin‐A MOMs were strongly correlated with hCG MOMs in the cases (r=0.73, p