Cervical leukocyte sub-populations in idiopathic preterm labour

OBJECTIVE: To investigate cervical epithelial leukocyte sub-populations in pregnant women with a history of idiopathic preterm labour.

METHODS: A prospective observational study was undertaken of 106 women with a past history of idiopathic preterm delivery following spontaneous labour. A cytobrush was used to sample the epithelium of the cervix at 12-16 weeks of gestation and again 8 weeks later. All women had investigations for cervical and vaginal infection as well as serial transvaginal ultrasonography of their cervix; the mode and gestation at delivery were recorded. Leukocyte sub-populations were examined using immunocytochemistry, and the number of leukocytes per total cell count was calculated.

MAIN OUTCOME MEASURES: Cervical epithelial leukocytes populations were (1) described in pregnancy, (2) observed over increasing gestation, (3) analysed in women who developed marked cervical shortening and (4) in those whose preterm labour recurred.

RESULTS: There was no significant change in cervical epithelial leukocyte populations during the second trimester of pregnancy. There was no association between cervical leukocytes and cervical shortening. Women with idiopathic preterm labour that recurred had fewer cervical macrophages at the beginning of the second trimester of pregnancy than those whose subsequent pregnancy progressed beyond 35 weeks of gestation.

CONCLUSIONS: Cervical epithelial macrophages may serve to prevent recurrent preterm labour, possibly by preventing ascending infection.