Leukocytic Invasion of the Ovine Cervix at Parturition

Objective: The aim of this study was to use the activity of a leukocyte-specific enzyme, myeloperoxidase, to quantify changes in leukocyte concentration in the ovine cervix during pregnancy. Methods: Cervical tissue was collected under halothane general anesthesia from 26 sheep at different stages of gestation, in the nonpregnant state, and postpartum. Myeloperoxidase activity was used to assess the degree of leukocytic infltration of the tissue. Results: Myeloperoxidase activity was low in cervices from nonpregnant ewes and did not increase during pregnancy until the onset of labor. Myeloperoxidase activity decreased after parturition. Conclusion: Labor in sheep is associated with leukocytic invasion of the cervix. This observation suggests that leukocytes could participate in cervical connective-tissue reorganization during dilatation at parturition and in postpartum involution of the cervic in this species.