Study population
Study participants were identified using obstetrical delivery ICD10
encounter codes and sonogram CPT codes. Patients were included in the
study if meeting the following screening TVUS and delivery criteria: age
between 18 to 50 years, underwent TVUS CL screening at NYULH Maternal
Fetal Care Center (MFCC) between 18 weeks 0 days – 23 weeks 6 days
gestation during a routine anatomic survey, and delivered a live neonate
at NYULH Tisch Hospital in the year 2018. Screened patients with
multiple gestation pregnancy, medically indicated preterm birth, uterine
anomalies, or cervical cerclage in situ were excluded. Enrolled
patients were also excluded if TVUS cervical images were not
electronically available from the medical record to review or if
available images were suboptimal for assessment of the cervix.
Demographics, clinical characteristics, and obstetrical outcomes were
manually collected for all patients; short interpregnancy interval was
defined as <18 months. As several of the predetermined
exclusion criteria are known risk factors for PTB, we anticipated a
relatively low-risk final study population; to determine the overall PTB
rate at our institution, a post-hoc evaluation of all excluded patients
was performed for gestational age (GA) at delivery to identify the
number of PTBs inadvertently excluded from final analysis of the study
cohort.