Light-induced fluorescence of the human cervix decreases after prostaglandin application for induction of labor at term

Objective: To define the changes in cervical light-induced fluorescence (LIF), an index of cross-linked collagen, after the use of locally applied prostaglandin preparations for labor induction at term and the correlation between LIF and Bishop-Score. Study design: The characteristic LIF of cervical collagen was measured from the surface of the cervix using a specially designed instrument (collascope) in 41 gravidas undergoing labor induction at term by prostaglandins. LIF and Bishop-Score were obtained directly before and 4 h after the administration of prostaglandin. Paired Student's t-test, Wilcoxon Signed Rank test, Linear Regression, Spearman correlation and Fisher Exact test were used as appropriate. Results: Cervical LIF decreased significantly after prostaglandin application (0.982 ± 0.04 [before] to 0.885 ± 0.037 [after], p = 0.025). The decrease in LIF correlated with the initial LIF before PG-application (r = 0.61). The Bishop-Score increased in all 41 patients. No correlation was found between LIF versus Bishop-Score. Conclusions: Cervical application of prostaglandins decreases the amount of cross-linked collagen as measured by LIF. This effect was observed only in patients with a prior high cross-linked collagen.