Unexplained elevated serum hCG is associated with raised amniotic fluid erythropoietin levels in second-trimester pregnancies

Objective: This study was designed to investigate the association between t he concentrations of maternal serum hCG and amniotic fluid erythropoietin d uring the second trimester of pregnancy. Methods: In a prospective case-con trol study, 42 consecutive singleton pregnancies showing unexplained elevat ed serum hCG concentrations (>2.0 multiples of the median, MoM) in Down's s yndrome screening and 27 control pregnant women undergoing midtrimester amn iocentesis because of a previous cytogenetic abnormality were studied. Resu lts:The mean amniotic fluid erythropoietin concentration in the study group was 1.8 (range 0.61-8.7) MoM, whereas it was 1.1 (range 0.71-3.96) MoM in the controls (p = 0.035). A significantly increasing relationship (p < 0.05 ) was found between the concentrations of maternal serum hCG and amniotic f luid erythropoietin. Conclusions: The results of the current study revealed in vivo the association between elevated hCG and amniotic fluid erythropoi etin levels which, in turn, supports the concept of early placental damage. The underlying pathology seems to be sufficient to cause an erythroblastic response.