Cervical sliding sign; does it have a contribution in cases of threatened preterm labor in singleton pregnancies with intact membranes?

Objective: To investigate the contribution of the cervical sliding sign to conventional cervical length measurement in patients at risk of preterm labor.

Methods: The study, performed as a prospective cohort study, included patients admitted to a tertiary research hospital with a diagnosis of threatened preterm labor. The participants were divided into two groups: those who gave birth before and after 37 weeks of gestation. The clinical and demographic characteristics, cervical length, presence of a short cervix (SC), and cervical sliding sign (CSS) were compared between the groups. Furthermore, correlation and regression analyses were conducted to investigate the relationship between the presence of a SC, the presence of CSS, and the coexistence of these two findings with preterm delivery, as well as the interval between the symptoms and delivery being less than four weeks.

Results: The study included 77 patients who delivered prematurely and 65 patients who delivered at term. The following variables were significantly lower in the preterm delivery group: cervical length, gestational age at delivery, neonatal weight, and time between the first examination and delivery (p = 0.003, <0.001, <0.001 and < 0.001, respectively). A higher percentage of women in the preterm delivery group exhibited a diagnosis of a SC, the presence of CSS, and the coexistence of both conditions (p = 0.002, 0.012 and 0.018, respectively). The results of the logistic regression analysis indicated that the odds ratios for preterm delivery were 3.3 in the presence of a SC alone, 2.67 in the presence of CSS alone, and 2.85 in the association of both findings (p = 0.003, 0.013 and 0.021 respectively). The odds ratios for delivery in less than four weeks were 3.08 in the presence of a SC alone, 3.4 in the presence of CSS alone, and 3.54 in the association of both findings (p = 0.004, 0.002 and 0.005 respectively).

Conclusion: In singleton pregnant women presenting with threatened preterm labor, the presence of CSS is associated with an increased risk of preterm delivery and a decreased presentation-to-delivery interval. However, its contribution to conventional cervical length measurement appears to be relatively limited.