The Association of Second-Trimester Cervical Length and Gestational Age at Delivery [ID 2683538

Abstract

INTRODUCTION: Second-trimester transvaginal cervical length (TVCL) under 2.5 cm is a well-established risk factor for preterm birth, although few studies have evaluated delivery outcomes in “normal” cervical length groups. We aimed to evaluate the association of normal TVCL (2.5 cm or greater) tertiles on gestational age (GA) at delivery. METHODS: This is a retrospective cohort study of patients eligible for vaginal birth with singleton term gestations and normal TVCL (at 16–24 weeks of gestation) delivering at a tertiary care center June 2022 to June 2023. Mean GA at delivery and rates of term deliveries were compared by TVCL tertiles (T1: 2.5–3.49 cm, T2: 3.5–4.49 cm, and T3: 4.5 cm or greater). Multivariable logistic regression was used to control for potential confounders. Institutional review board approval was obtained. RESULTS: Of 1,034 eligible deliveries, 984 (95.2%) were term (37 0/7 weeks or greater). Patients with TVCLs in T2 and T3 were significantly more likely to have a term delivery than patients with TVCL in T1 (T2 96.0% versus T1 90.9%, P=.007; T3 96.2%, P=.03). Compared to T1, those with TVCLs in T2 and T3 also had increased odds ratio (OR) of a term birth (OR 2.4 [CI, 1.2–4.8] and OR 2.55 [CI, 1.03–6.7], respectively). After adjusting for confounders, this relationship remained statistically significant (T2 adjusted OR 3.05 [CI, 1.4–6.6]; T3 3.91 [CI, 1.3–11.4]). CONCLUSION: Patients with longer TVCL measured at anatomy ultrasound are significantly more likely to have a term delivery, even after adjusting for confounders. These results can be used to guide patient counseling and expectations for labor and delivery outcomes.