Developing a quality assurance program for transvaginal cervical length measurement at 18–21 weeks’ gestation

Abstract

Background Preterm birth is the leading cause of death in children under the age of five years. Transvaginal cervical length (TVCL) assessment can be used to predict preterm delivery risk at the mid‐trimester scan. To optimise the screening tool, developing and maintaining quality standards is important. Aims To develop an Australian reference range for TVCL at 18.0–21.0 weeks’ gestation, quality standards for measurement and audit mechanisms for ultrasound operators. Materials and Methods A retrospective audit was performed of consecutive patients scanned at 18.0–21.0 weeks’ gestation. Each TVCL measurement ultrasound image was reviewed, and exclusions were made based on a defined set of quality criteria. Fractional polynomial Bayesian methodology was used to establish a reference range. Central tendency, dispersion plots and cumulative sum charts for operators in the original reference range cohort were created. These plots were then applied to a second validation cohort of operators to establish the efficacy of this quality assurance audit tool. Results Median TVCL from 1031 participants was 36.0 mm (interquartile range 32.7–40.0 mm), which was independent of gestational age. The quality audit tool was applied to 15 operators from the reference cohort with a mean cervix length multiple of the median of 1.01 and a mean SD log10 cervix length multiple of the median of 0.06. Of the 22 operators in the validation cohort, 20 (90.9%) demonstrated ideal or acceptable central tendency results, and 19 (86.4%) remained in the appropriate cumulative sum zone. Conclusion An Australian cervix length measurement reference range at 18.0–21.0 weeks’ gestation has been developed along with a validated quality assurance audit tool for ultrasound operators.

Cervical assessment certification and its impact on performance quality in the context of universal cervical screening

“…Acceptability of undergoing TVCL examination was 100% among the population at high risk for PTB after implementation of universal screening, and 95.3% in the low‐risk group, with an overall acceptance rate of 95.5%, in keeping with recently published studies 30–32 …”

“…Acceptability of undergoing TVCL examination was 100% among the population at high risk for PTB after implementation of universal screening, and 95.3% in the low-risk group, with an overall acceptance rate of 95.5%, in keeping with recently published studies. [30][31][32] The present study is the first one to evaluate the performance of the ultrasound operators using a qualitative scoring system based on FMF certification in the context of universal cervical screening. Despite the retrospective approach, its strength relies on non-biased examinations and a large number of scans.…”

Expected‐value bias in mid‐trimester preterm birth screening

“…Inner dashed rectangle indicates ideal CL multiples of the median (MoM) range (0.95–1.05); outer dashed rectangle indicates acceptable CL MoM range (0.90–1.10). Horizontal and vertical dotted lines, at 0.06 and 0, respectively, are according to Filce et al 26 …”

Implementing a Universal Cervical Length Screening Program in a Large Hospital System: It Takes Some Time to Achieve Consistent Results

“…Other variables such as physiological changes or/and contractions might account for CL variations [26, 27]; however, the main source of error is the sonographer’s technique. Filce et al [28] proposed an auditable program to improve the reliability of CL measurements consisting in creating “optimal” mean and dispersion values. Data from each US operator can be audited for evaluation of the individual variability.…”