Local collagen turnover in human foetal membranes during full term vaginal delivery.

Objectives: To investigate if changes in local metabolism of collagens type I and type III may contribute to the term rupture of the foetal membranes.

Study Design: In extracts from membranes taken along the rupture line and near the site of the umbilical cord attachment to the placenta, we measured concentrations of specific markers of collagen synthesis, namely C-terminal propeptide of type I collagen (PICP) and N-terminal propeptide of type III collagen (PIIINP), as well as the concentration of the pyridinoline cross-linked C-terminal telopeptide of type I collagen (ICTP), which reflects the rate of collagen type I breakdown.

Results: The mean concentrations of PICP and PIIINP did not differ statistically between the two examined groups of samples. The mean ICTP concentration was threefold higher in extracts prepared from samples taken near the rupture site, than from membranes derived from the proximity of the umbilical cord attachment.

Conclusions: Term rupture of foetal membranes is accompanied by increased local degradation of type I collagen fibrils at the rupture site, whereas the biosynthesis of collagen types I and III remains unchanged.