BIOCHEMICAL ANALYSES OF MESENCHYMAL FLUID IN EARLY-PREGNANCY

OBJECTIVE: Our purpose was to compare the biochemical composition of t he fluid contained in pathologic and physiologic cavities in early pre gnancy. STUDY DESIGN: The level of urea, creatinine, electrolytes, enz ymes, total protein, and alpha-fetoprotein and the affinity of alpha-f etoprotein for concanavalin A Sepharose was measured in samples of ves icular fluid from complete (n = 2) and partial (n = 1) mole, nuchal fl uid (n = 4), and cystic hygroma fluid (n = 4). For comparison samples of maternal serum (n = 32), amniotic fluid (n = 32), coelomic fluid (n = 15), and fetal blood (n = 13) were obtained from normal pregnancies at 10 to 16 weeks' gestation. RESULTS: Urea concentration was lower, whereas sodium, potassium, and total protein concentrations were highe r in vesicular fluid than in amniotic and coelomic fluid. Urea, creati nine, sodium, potassium, chloride, and beta(2)-microglobulin concentra tions did not vary between nuchal or cystic hygroma fluid and amniotic fluid or fetal serum. The concentration of total protein in nuchal an d hygroma fluid was significantly lower than in fetal serum and signif icantly higher than in amniotic fluid. The amniotic fluid contained ex tremely high tau-glutamyltransferase concentration compared with the o ther fluids and fetal serum. Alkaline phosphatase and amylase were not detectable in coelomic fluid, fetal serum, or nuchal and hygroma flui d. The nuchal and hygroma fluid composition was similar except: for to tal protein and alpha-fetoprotein concentrations, which were significa ntly higher in nuchal than in hygroma fluid. The vesicular fluid from the partial mole, fetal serum, and nuchal and hygroma fluid contained extremely high alpha-fetoprotein concentrations, which were significan tly higher that those found in amniotic fluid. In complete mole alpha- fetoprotein molecules were of the yolk sac type, whereas they were of the liver type in nuchal and hygroma fluid. CONCLUSIONS: The compositi on of vesicular fluid in complete mole reflects a possible origin from the maternal plasma, yolk sac, and trophoblast, whereas the compositi on of nuchal and cystic hygroma fluid suggests a leakage from the feta l circulation.