Developing a quality assurance program for transvaginal cervical length measurement at 18-21 weeks' gestation

Area of Science:

• Obstetrics and Gynecology
• Medical Imaging
• Biostatistics

Background:

• Preterm birth is a leading cause of mortality in children under five.
• Transvaginal cervical length (TVCL) assessment during mid-trimester scans aids in predicting preterm delivery risk.
• Establishing quality standards is crucial for optimizing TVCL as a screening tool.

Purpose of the Study:

• To develop an Australian reference range for TVCL measurements between 18.0 and 21.0 weeks' gestation.
• To establish quality standards for TVCL measurement.
• To create audit mechanisms for ultrasound operators.

Main Methods:

• Retrospective audit of 1031 consecutive patient scans at 18.0-21.0 weeks' gestation.
• Exclusion of images based on defined quality criteria.
• Application of fractional polynomial Bayesian methodology to establish the reference range and a quality assurance audit tool.

Main Results:

• A median TVCL of 36.0 mm (IQR 32.7-40.0 mm) was determined, independent of gestational age.
• The quality audit tool demonstrated efficacy in a validation cohort, with 90.9% of operators showing acceptable central tendency and 86.4% within the appropriate cumulative sum zone.

Conclusions:

• An Australian reference range for TVCL at 18.0-21.0 weeks' gestation has been successfully developed.
• A validated quality assurance audit tool for ultrasound operators has been created to ensure measurement accuracy.