Evaluation of effectiveness of prophylactic cerclage of a short cervix according to interleukin-8 in cervical mucus

Objective This study was undertaken to compare rates of preterm delivery according to cervical mucus interleukin-8 (IL-8) among women who underwent cerclage because of a short cervix. Study design This retrospective study included 16,508 patients whose cervical length and cervical mucus IL-8 concentrations were measured between 20 and 24 weeks. A short cervix was defined by a length of 25 mm or less, whereas IL-8 concentrations exceeding 360 ng/mL were considered high. Whether to perform cerclage was decided by clinicians without consideration of IL-8 concentrations. Results Among all subjects, a significantly smaller percentage of subjects avoided delivery before 37 weeks when cervical mucus IL-8 was elevated ( P = .0302) or the cervix was short ( P P = .01; before 34 weeks, 4% vs 13.6%, P = .03). In contrast, when cervical mucus IL-8 was high, delivery before 37 weeks was more likely with than without cerclage (78% vs 54.1%, P = .03). Conclusion With normal cervical mucus IL-8, cerclage treatment for cervical shortening may reduce the rate of preterm delivery, but with elevated cervical mucus IL-8 cerclage may be harmful.