Impact of Sonographer Experience, Insonation Angle, and Bladder Filling on Uterine Artery Doppler Measurements in the First Trimester of Pregnancy

Objective

To investigate the influence of different measurement conditions and ultrasound training level on uterine artery pulsatility index (UtA-PI) measurements as required for combined first trimester preeclampsia (PE) screening.

Methods

This was a prospective study of consecutive patients with singleton pregnancies presenting for an ultrasound examination between 11 and 14 weeks' gestation. UtA-PI measurements were conducted by residents in training and repeated by experienced sonographers thereafter. UtA-PI measurements were conducted under different examination conditions. First, the trainee sonographers performed transabdominal sagittal and transverse UtA-PI measurements without bladder filling. These measurements were then repeated by the expert sonographers. Additionally, the expert sonographers also performed transvaginal UtA-PI measurements and transabdominal measurements with bladder filling. Statistical analysis was conducted with the statistical software R and included descriptive statistics as well as 2-sided paired t tests.

Results

A total of 100 women were included in the study. Mean age was 31.7 ± 4.92 years and mean gestational week was 12.5 ± 0.53 weeks. A total of 56% were nulliparous and 44% were parous. UtA-PI was significantly lower if performed by a sonographer in training versus an experienced sonographer (P = .031). No significant difference was observed in comparing transverse and sagittal techniques (P = .241). There was also no significant difference in transabominal versus transvaginal measurements (P = .806) and with an empty versus full bladder (P = .444).

Conclusion

Experience of sonographer has a significant impact on UtA-PI. Supervised onsite training is necessary to improve reliability and consistency of UtA-PI measurements and make PE screening reliable for implementation in a universal screening setting.