Figure 1 presents the concentrations of fetuin A in amniotic fluid from euploid and trisomy 21 pregnancies plotted against individual patients. In addition, gestational age is correlated with fetuin A; the more advanced the gestation, the higher the concentration of the hormone in amniotic fluid for both groups (r = 0.44, P = 0.029 for euploid pregnancies and r = 0.55, P = 0.005 for DS pregnancies). On the other hand, its levels are not correlated with maternal age (P = 0.42). Here, AHSG is linked to trisomy 21.