916 The association between preterm birth and ultrasound visualization of the cervical gland area

Abstract

Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality. Yet, transvaginal ultrasound (TVUS) cervical length (CL) screening suboptimally predicts spontaneous PTB (SPTB). Abnormal remodeling of glandular crypts along the cervical canal may contribute to increased PTB risk via premature cervical ripening, which may correspond to no visualizable cervical gland area (CGA) on TVUS (Figure 1). This study aims to determine if no visualizable (“absent”) CGA at CL screening is predictive of PTB. We performed a retrospective cohort study of pregnant women carrying a singleton gestation who had CL screening between 180/7 – 236/7 weeks gestation and delivered a live neonate at a single academic institution between 1/1/18 and 12/31/18. 1000 of the most recent deliveries in 2018 were screened for inclusion. Patients with uterine anomalies, cerclage, suboptimal imaging, or with indicated preterm delivery were excluded. TVUS images were assessed for CL, CGA visualization, and if present, quantitative CGA measurements were performed. The primary outcome was SPTB prior to 37 weeks. Absent and present CGA groups were compared using χ2, Fischer’s exact, T-test, and logistic regression with significance at p<0.05. 784 women were included. Demographic and medical characteristics of the sonographically absent and present CGA groups were similar. The absent CGA group was more likely parous and to receive progesterone supplementation (77 vs 40% and 17 vs 4% respectively, p=0.03). Overall PTB rate was 2.7% and rate of absent CGA was 2.3%. Absent CGA was significantly associated with delivery <37, <34, and <32 weeks (p<0.005) (Table 1). Quantitative CGA width, length, and area did not individually correlate with PTB. A multiple logistic regression model demonstrated 8% improvement for prediction of PTB <37 weeks with the addition of CGA evaluation compared to CL alone (p<0.001). Patients with no visualizable CGA were more likely to experience spontaneous preterm delivery. Assessment of CGA visualization may improve the performance of CL screening for predicting SPTB.View Large Image Figure ViewerDownload Hi-res image Download (PPT)