ABSTRACT
Parturition involves a complex interplay of maternal and fetal factors. An understanding of the physiological mechanisms involved in maternal adaptations would be of great benefit in the diagnosis, management, and outcome of dystocic parturition, an important problem in human health care and animal production. In tjis review, we consider the histofunctional changes in the uterine cervix that are essential for sucessful vaginal delivery and focus on work from our laboratory. The functions of the uterine cervix change considerably during pregnancy. As the uterus enlarges to accommodate the growing fetus, the cervix behaves essentially as a barrier. At term, however, the cervix softens and dilates through a process known as cervical ripening. This process is extremely complex and involves interactions between different cellular compartments and the extracellular matrix, as well as properly timed biochemical cascades, and stromal infiltration by inflammatory cells. Since the main component of the uterine cervix is connective tissue, collagen remodeling is a key event for ripening and delivery. Moreover, because of their intrinsic mechanical properties, elastic fibers may be involved in the recovery of shape immediately after parturition. Despite the advances in our knowledge of cervical ripening, the signals responsible for initiating these changes remain to be elucidated. By understanding the mechanisms involved in these changes, it should be possible to adress complex issues such as cervical incompetence, pre- and post-term delivery, and proper "ripening" of the cervix in order to avoid surgical delivery.