Evolution of the elastic fiber network of the human uterine cervix before, during and after pregnancy. A quantitative evaluation by automated image analysis.

To assess the evolution of the elastic fiber network of the human uterine cervix before, during and after pregnancy, biopsy samples were obtained from 49 women. The high affinity of the polyphenolic compound (+)-catechin for elastin was used to stain the elastic fibers selectively, and enabled automated image analysis. In the human uterine cervix, the elastic fiber network is made up of: (1) fibers running parallel to the basement lamina of the epithelium, and (2) thinner, perpendicular fibers. Quantification using automated image analysis shows a decline in the cervical elastin content from a prepregnancy level of 1.33 +/- 0.08 (SEM) to 0.73 +/- 0.09% (Vv) at the end of pregnancy. In parallel with a constant decline, dissociation and disorganization of the fibers become more clearly evident as pregnancy progresses. However, by 5-7 weeks postpartum the elastic fiber network appears almost completely restructured. These changes support a role of elastin in the processes of cervical maturation and reconstruction during pregnancy and after delivery.