Collagen types in normal and prematurely ruptured amniotic membranes.

Collagen content in preterm amnions with premature rupture of the membranes was significantly lower than that of preterm amnions without premature rupture of the membranes. Collagen types were studied through sodium dodecyl sulfate-polyacrylamide gel electrophoresis in human amnions from pregnant women with or without premature rupture of the membranes. Collagen types I, III, and V were recognized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in all samples. In samples taken from preterm patients with premature rupture of the membranes, the ratios of III/I, III/V, and III/total collagen were significantly lower than those from ones without premature rupture of the membranes. The ratios of I/V, I/total collagen, and V/total collagen showed no change in gestations with and without premature rupture of the membranes, respectively. In term samples there was no significant difference in the ratios of all collagen types between those with and those without premature rupture of the membranes. Elastins were not demonstrable in amnion with and without premature rupture of the membranes. These studies suggest that the reduction of type III collagen content in amnion is related to the cause of premature rupture of the membranes, particularly in preterm samples.