Doppler sonography of uterine hemodynamics: a standardized transvaginal protocol for assessing uterine perfusion in infertile and fertile women

Abstract

Objectives: To describe a standardized transvaginal Doppler ultrasound protocol for assessing uterine artery hemodynamics and subendometrial perfusion, and to evaluate its ability to differentiate infertile from fertile women in a Nigerian tertiary hospital setting. Methods: In this prospective comparative cross-sectional study, 300 infertile women and 300 fertile controls underwent a structured transvaginal Doppler examination during the mid-luteal phase. The protocol involved: (1) B-mode confirmation of cycle phase and anatomy, (2) Color Doppler localization of uterine arteries at the cervicocorporal junction, (3) Pulsed-wave Doppler sampling with angle correction (<60°) to obtain mean pulsatility index (PI) and resistivity index (RI), and (4) Color Doppler mapping to classify subendometrial blood flow into zones (1-3). Discriminative ability was assessed by comparing indices and flow zones between groups. Results: The protocol was successfully completed in all participants with excellent technical feasibility and good intra-operator consistency (no significant side-to-side difference in indices, p>0.05). Infertile women exhibited significantly higher mean uterine artery RI (0.79±0.07 vs. 0.73±0.06, p<0.001) and PI (2.15±0.56 vs.1.69±0.30, p<0.001). Subendometrial flow was abnormal (Zone 1 or 2) in 45.7% of infertile women versus 0% of controls (p<0.001). Using an RI cut-off of >0.8 yielded a sensitivity of 45.0% (95% CI: 39.3-50.8%) and a specificity of 100% (95% CI: 98.8-100%) for differentiating infertility status. The PI cut-off of >3.0 showed low sensitivity (4.0%, 95% CI: 2.2-6.8%), suggesting that population-specific thresholds may be needed. Conclusion: The described Doppler protocol is a feasible andreproducible imaging tool for identifying impaired uterine perfusion associated with infertility. Its integration into routine pelvic ultrasound can provide critical functional information to guide patient management in resource-constrained settings. However, prospective validation of its predictive value for pregnancy outcomes is needed.