Figure 1. Correlation between fetal hematocrit and plasma IL-6 concentration among 16 fetuses with Rh alloimmunization who underwent cordocentesis for suspected anemia.
There was a significant negative correlation between the fetal hematocrit and plasma IL-6 concentration (Spearman’s rho −0.68, p=0.004). The interrupted line represents the cutoff value of IL-6 concentration for the diagnosis of FIRS. Four fetuses (“empty” dots) were diagnosed with FIRS.