(1175) Predicting gestational latency using serial monitoring among nulliparous, singleton pregnancies with low-normal mid-trimester cervical lengths

Friday, January 31, 2025

4:00 PM – 6:00 PM

Submitting Author and Presenting Author(s)

Sandhya Chandrasekaran, MD, PhD (she/her/hers)

OB/GYN Resident Physician
University of Chicago School of Medicine
Chicago, IL, United States

Coauthor(s)

VM

Vanya Manthena, MPH

Research Coordinator
Pritzker School of Medicine, University of Chicago
Chicago, Illinois, United States
AR

Andrew Rausch, MD

Assistant Professor
Pritzker School of Medicine, University of Chicago
Chicago, Illinois, United States
RL

Ryan E. Longman, MD

Associate Professor
Pritzker School of Medicine, University of Chicago
Chicago, Illinois, United States
Ashish Premkumar, MD, PhD (he/him/his)

Assistant Professor
Biological Sciences Division, University of Chicago
Chicago, Illinois, United States

Objective: Preterm births account for approximately 70% of neonatal deaths and 36% of infant deaths. In this setting, cervical length screening is of utmost importance as a predictor of preterm birth. Nulliparous patients pose a particularly difficult challenge with respect to counseling reading cervical insufficiency given their lack of pregnancy history. We sought to explore predictive trends in serial CLs associated with preterm birth in this otherwise low-risk population.

Study Design: We performed a retrospective case control analysis of all nulliparous, singleton pregnancies from 2021 to 2023 who underwent an anatomy scan with an initial low-normal cervical length (CL) >25mm and < 30mm followed by at least one serial CL with available gestational age at the time of delivery. The primary outcome was gestational latency (GL), defined as time of diagnosis of low-normal cervical length to delivery. Trajectory analysis was performed to gauge CL changes as a function of time from delivery between the two groups, using linear regression models. Bivariate analyses were performed.

Results: 30 nulliparous, singleton pregnancies with initial low-normal CL were evaluated, with 23 resulting in term deliveries (“tb”, >= 37 weeks) and 7 resulting in preterm deliveries (“ptb”, < 37 weeks, Table). When plotting serial CLs as a function of time, CL in the “tb” controls generally increased with GL (slope: 0.05), while CLs in the “ptb” controls demonstrated a modest decrease with GL (slope: -0.12). Importantly, there was a high degree of individual variability in CL trajectories among those whose pregnancies resulted in preterm deliveries (Figure).

Conclusion: 23% of individuals with a low-normal cervix will deliver preterm. However, high individual variability exists across groups. These data point to the use of serial monitoring in the setting of low-normal cervix and the need for further work into deciphering individuals factors contributing to these differences to drive novel interventions aimed at stabilizing the cervix with the goal of minimizing risk of preterm birth.