<b>Impact of Doppler Indices in Uterine Hemodynamics on Primary Infertility and Secondary Infertility</b>

Background: Uterine perfusion is an important component of endometrial receptivity and may influence reproductive potential in women with infertility. Doppler ultrasonography provides a non-invasive method for assessing uterine artery blood-flow resistance through pulsatility index, resistive index, and systolic-to-diastolic ratio. Objective: This study aimed to compare uterine artery Doppler indices between women with primary and secondary infertility and to assess their relationship with associated gynecological conditions. Methods: An observational comparative cross-sectional study was conducted among 56 infertile women, including 33 with primary infertility and 23 with secondary infertility. Transvaginal color Doppler ultrasonography was used to assess uterine artery pulsatility index, resistive index, and systolic-to-diastolic ratio. Associated conditions, including polycystic ovary syndrome, endometrial polyps, and fibroids, were recorded. Group comparisons were performed using parametric and non-parametric tests, and categorical associations were assessed using chi-square or Fisher’s exact testing. Results: Women with primary infertility had higher pulsatility index, resistive index, and systolic-to-diastolic ratio than women with secondary infertility: 2.97 ± 0.44 versus 2.34 ± 0.31, 0.88 ± 0.05 versus 0.77 ± 0.06, and 6.73 ± 0.89 versus 5.17 ± 0.90, respectively. All Doppler differences were statistically significant, with large effect sizes. PCOS, endometrial polyps, and fibroids were not significantly associated with infertility type. Conclusion: Uterine artery Doppler indices were significantly higher in women with primary infertility, suggesting greater uterine vascular resistance. Doppler assessment may serve as an adjunctive tool in infertility evaluation, although larger prospective studies are needed.