[Detection of erythropoietin in amniotic fluid]

To investigate the concentrations of amniotic fluid erythropoietin in normal and risk pregnancies.

The concentrations of erythropoietin were measured in 150 samples of amniotic fluid. The samples were obtained by amniocentesis and amniotomia and were analysed using an enzyme-linked immunosorbent assay (ELISA). Results were available within 6 hours. The intra-assay variation was 6.4%, the inter-assay variation 7.2%.

The range of erythropoietin concentration in all samples was between 0.23 and 80 U/L and in a defined group of normal pregnancies between 1.20 and 6.53 U/L (10%-90% percentile). Correlation was found between the concentration of erythropoietin and maternal hypertension (p = 0.0159), amnion infection syndrome in combination with premature birth (p = 0.0593), fetal growth retardation (p = 0.784), and base-excess (p = 0.0487). Elevated erythropoietin concentrations were found in a defined risk group with Apgar scores below 7 after 1 minute (p = 0.072) and after 5 minutes (p = 0.0037). There is a connection between postpartal transfer to the intensive-care unit and elevated erythropoietin concentrations (p = 0.073). No influence is exercised by the child's sex on the concentration of erythropoietin. No significant connection was found between the level of erythropoietin and smoking during pregnancy, volume of amniotic fluid and maturity at birth. A critical erythropoietin concentration could be postulated at 12 U/L. Children with higher levels showed heavy and severe disorders.

Elevated erythropoietin levels in amniotic fluid indicate prolonged fetal hypoxaemia. Using the ELISA-technique a rapid prepartal determination of such situations is possible and might be helpful in the clinical procedure.