Uterine Artery Doppler Disturbance Index Is Associated with Endometrial Perfusion and Clinical Pregnancy in IVF/ICSI: A Single-Center Retrospective Cohort Study.

OBJECTIVES: Uterine artery Doppler is widely used to gauge endometrial receptivity in In Vitro Fertilization (IVF)/Intracytoplasmic Sperm injection (ICSI), but a single pulsatility index (PI) measurement from bilateral uterine arteries at a single time point captures neither the full extent of inter-side asymmetry nor the cycle-to-cycle variability that may better reflect a hostile peri-implantation environment. We defined a Uterine Artery Doppler Disturbance index (UADD-PI and UADD-RI) as the coefficient of variation of bilateral pulsatility and resistance indices measured across 3 consecutive cycles and tested its association with 3-D power-Doppler endometrial perfusion and clinical pregnancy in a retrospective single-center cohort. METHODS: We retrospectively reviewed the electronic medical records of 437 consecutive first IVF/ICSI cycles (173 fresh embryo transfer, 264 frozen embryo transfer) treated at a single tertiary reproductive medicine center between January 2023 and April 2026. As part of routine pre-transfer evaluation at our center, bilateral uterine artery PI and RI were obtained on hCG-trigger day (fresh) or progesterone day 5 (FET), and on the corresponding day of 2 preceding natural or stimulated cycles. UADD was calculated as 100 × SD/mean of the 6 measurements obtained from both uterine arteries across 3 consecutive cycles (2 sides × 3 cycles). Endometrial vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) were obtained by 3-D power-Doppler with VOCAL and retrieved from the picture-archiving system. Primary outcome was clinical pregnancy; ongoing pregnancy and live birth were secondary. Multivariable logistic regression, restricted cubic splines, and 1000-resample bootstrap internal validation were used. RESULTS: UADD-PI was inversely correlated with VI (Spearman ρ = -0.46), FI (ρ = -0.28), and VFI (ρ = -0.56; all p < .001). Each 5-percentage-point increment in UADD-PI was independently associated with lower clinical pregnancy (adjusted OR 0.75, 95% CI 0.64-0.89, p < .001) after controlling for age, BMI, log-AMH, endometrial thickness, embryo grade, cycle type, and 3-D VI. Adding UADD-PI to a baseline model raised the AUC from 0.657 to 0.762 (Δ 0.105, p < .001); calibration was acceptable (Hosmer-Lemeshow p = .349; calibration slope 0.94; Brier 0.173 versus null Brier 0.207). The dose-response relationship was monotonic and statistically linear (non-linearity LR χ2 = 1.44, p = .487). CONCLUSIONS: A bilateral, cycle-aggregated UADD index captures information that a single PI measurement misses and is independently associated with endometrial perfusion and pregnancy outcome. Because the analysis is retrospective and single-center, these findings are hypothesis-generating; UADD is best viewed as a potential complement to-rather than a replacement for-conventional Doppler indices and requires external prospective validation before any clinical application.