Glycosaminoglycans and collagen in human amnion from pregnancies with and without premature rupture of the membranes.

Glycosaminoglycans and collagen were measured in dried samples of human amnion from pregnancies with and without premature rupture of the membranes. The major sulphated glycosaminoglycans were dermatan and chondroitin sulphates. The concentration of sulphated glycosaminoglycans decreased significantly towards term in both groups of patients (with, r=--0.720, and without, r=-0.631, premature rupture of membranes), the decrease occurring earlier in gestation in the PROM group (P less than 0.005). There was a positive correlation between the sulphated glycosaminoglycan and collagen concentrations in both groups of samples (with, r = 0.697 and without, r = 0.493, premature rupture of membranes). The only unsulphated glycosaminoglycan identified in amnion was hyaluronate which was present in higher concentrations (P less than 0.005) in term samples (10.67 +/- 5.5 microgram/mg) than in pre-term samples (5.45 +/- 2.98 microgram/mg). There was a negative correlation between the hyaluronate and collagen concentrations (r = -0.455). The associations between decreasing concentration of both sulphated glycosaminoglycan and collagen with increasing concentrations of hyaluronate in amnion are consistent with observed changes in the tensile properties of the amnion towards term and are explicable in terms of accepted mechanisms of connective tissue remodelling.