Increased plasma levels of beta2-microglobulin, cystatin C and beta-trace protein in term pregnancy are not due to utero-placental production.
OBJECTIVE
To study concentration gradients of the low molecular mass proteins, beta2-microglobulin, cystatin C and beta-trace protein, between the uterine and ante-cubital veins, the umbilical artery and vein and in the amniotic fluid compartment.


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 beta2-microglobulin, cystatin C or beta-trace protein between the uterine and antecubital veins. There were no correlations between the protein levels in the compartments.


CONCLUSIONS
The utero-placental unit does not contribute significantly to the maternal levels of beta2-microglobulin, cystatin C and beta-trace protein in normal pregnancy, and the proteins are not likely to be transferred across the placental barrier.
Kristensen
K
K
Department of Obstetrics and Gynecology, University Hospital, Lund, Sweden. karl.kristensen@med.lu.se
Strevens
H
H
Lindström
V
V
Grubb
A
A
Wide-Swensson
D
D
D000328:Adult; D000653:Amniotic Fluid; D002585:Cesarean Section; D055316:Cystatin C / Q000097:blood*; D005260:Female; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000097:blood*; D054834:Lipocalins / Q000097:blood*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000097:blood*; D014469:Umbilical Arteries; D014471:Umbilical Veins; D014599:Uterus / Q000098:blood supply / Q000378:metabolism*; D001613:beta 2-Microglobulin / Q000097:blood*
D055316:Cystatin C; D054834:Lipocalins; D001613:beta 2-Microglobulin; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase