Increased plasma levels of ß₂‐microglobulin, cystatin C and ß‐trace protein in term pregnancy are not due to utero‐placental production

Abstract

Objective. To study concentration gradients of the low molecular mass proteins, ß₂‐microglobulin, cystatin C and ß‐trace protein, between the uterine and ante‐cubital veins, the umbilical artery and vein and in the amniotic fluid compartment. Material and methods. The study comprised 27 healthy women with uncomplicated pregnancies undergoing caesarean section at term. Samples were collected simultaneously and paired t‐tests were used to compare mean plasma concentrations. Results. There was no significant concentration gradient in the plasma levels of ß₂‐microglobulin, cystatin C or ß‐trace protein between the uterine and antecubital veins. There were no correlations between the protein levels in the compartments. Conclusion. The utero‐placental unit does not contribute significantly to the maternal levels of ß₂‐microglobulin, cystatin C and ß‐trace protein in normal pregnancy, and the proteins are not likely to be transferred across the placental barrier.

• ß₂‐microglobulin
• ß‐trace protein
• creatinine
• cystatin C
• placenta
• plasma protein
• urate

Acknowledgements

We thank the Medicon Valley Academy and Dako Denmark A/S for financial support and for instigating the fruitful network that made this investigation possible.