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.