Can the cervical length in mid-trimester predict the use of vacuum in vaginal delivery?

OBJECTIVE: This study aimed to evaluate whether an increased cervical length (CL) measured in the mid-trimester is associated with vacuum-assisted vaginal delivery. METHODS: This retrospective cohort study included women who delivered vaginally in Seoul National University Bundang Hospital (n=820) and Boramae Medical Center (n=509) between January 2017 and February 2019. Multifetal pregnancies and preterm births before 37 weeks of gestation were excluded. Only those cases in which CL was measured at 18–22 weeks of gestation for the purpose of screening for preterm birth risk in each institution were analyzed (n=537). Other significant risk factors were reviewed. RESULTS: The median gestational age at delivery was 39.4 weeks (range, 37.0–41.6 weeks); 18.6% (100/537) were vacuum-assisted delivery. There was no relationship between mid-trimester CL and vacuum-assisted delivery (odds ratio [OR], 0.96; 95% confidence interval [CI], 0.57–1.62), while nulliparity was associated with a higher risk (OR, 3.64; 95% CI, 1.55–8.57) than multiparity. When the population was divided into 3 groups by CL range, vacuum-assisted delivery rates increased as CL length increased in nulliparous women. CONCLUSION: Mid-trimester CL did not predict the need for vacuum-assisted vaginal delivery.