The effect of bilateral pelvic neurectomy on cervical ripening in pregnant rats

Abstract Aims: To determine the effect of bilateral pelvic neurectomy (BPN) on cervical ripening in pregnant rats by measuring cervical extensibility and changes in collagen cross-linkages. Methods: Timed-pregnant rats were randomly laparotomized on days 9 or 10 of gestation and the pelvic nerves were exposed and either bilaterally transected, or left intact in sham control animals. The rats were sacrificed on day 18 and the uterine cervices obtained. Cervical ripening was assessed by cervical resistance-to-stretch, light-induced autofluorescence (LIF) of cross-linked collagen, and collagen changes analyzed by picrosirius polarization microscopy. Results: Measurements of extensibility and collagen cross-linkages indicated that after BPN the cervix was significantly more ripened than the cervix from sham control animals. Conclusion: BPN stimulates cervical ripening instead of inhibiting this event as previously proposed. Further studies in this area could be critical for developing treatments for dystocia, preterm labor, and cervical insufficiency.

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