Collagen degradation in the pregnant human cervix at term and after prostaglandin-induced cervical ripening.

The role of enzymatic collagen degradation in prostaglandin-induced and physiological cervical ripening was studied by determining collagenase and other proteolytic activity in extracts of cervical biopsies. Collagenase activity was assayed in a highly specific and sensitive system using native collagen type I as substrate. The intracervical application of sulprostone gel prior to termination of 1st trimester pregnancy led to a marked improvement in cervical dilatability. Collagenase and proteolytic activity were found to be significantly higher in postpartum samples than in specimens obtained from the nonpregnant or early pregnant cervix. After sulprostone treatment enzymatic activities were only marginally elevated. Analysis of extractable peptides showed that sub partu collagen was degraded in preference to noncollagenous proteins into very small fragments, whereas in the process of prostaglandin-induced cervical ripening collagen degradation appears to be of minor importance.