RELAXIN LEVELS IN AMNIOTIC-FLUID, EXTRAEMBRYONIC CELOMIC FLUID AND MATERNAL SERUM IN EARLY HUMAN-PREGNANCY

Separately identified samples of amniotic fluid and extraembryonic coelomic fluid together with maternal serum were collected from 22 women between 8 and 11 weeks of pregnancy and analysed for relaxin by immunoassay. Relaxin levels in maternal serum (median 1085 pg/ml; range 390-1259 pg/ml) were substantially higher than those in extraembryonic coelomic fluid (median 57.5 pg/ml; range 17-145 pg/ml; P < 0.0001; Mann-Whitney U-test). In turn, the levels of relaxin in coelomic fluid were higher than those in amniotic fluid (median 10 pg/ml; range 10-37 pg/ml; P < 0.0001; Mann-Whitney U-test). A linear correlation was found between relaxin levels in maternal serum and coelomic fluid (r = 0.68; P = 0.001) but there was no relation between levels in the other fluid compartments.