Uterine artery blood flow and microvessel density by vaginal color Doppler ultrasonography in embryo implantation failure

The purpose of this study was to investigate the clinical application of uterine artery blood flow parameters by vaginal color Doppler ultrasonography in patients with repeated embryo implantation failure and to examine the correlation between uterine artery blood flow parameters and microvessel density (MVD). We monitored the outcomes of in vitro fertilization and embryo transfer in eighty patients. We divided the patients into two groups: Pregnancy (successful pregnancy, n=50) and repeated implantation failure (more than two failures of in vitro fertilization-embryo transfer, n=30). The patients were subjected to vaginal color Doppler ultrasonography to measure endometrial thickness, peak systolic velocity/end diastolic velocity (S/D), pulsatility index (PI), resistance index (RI), and other uterine artery blood flow parameters. We found no significant differences in endometrial thickness (human chorionic gonadotropin endometrial thickness) and uterine artery blood flow parameters (S/D, PI) between the two groups. The RI value of endometrial blood flow was significantly higher in the repeated implantation failure group than that in pregnancy group. The endometrium MVD in the repeated implantation failure group was significantly lower than that of the pregnancy group. Spearman correlation analysis showed that S/D value of uterine artery blood flow in repeated implantation failure group was not correlated with MVD or uterine artery blood flow PI, but was positively correlated with RI. Endometrium MVD in patients with repeated implantation failure was significantly lower than that in patients with successful pregnancy during the implantation window. We also found a significant difference in uterine artery blood flow RI between the two groups. The uterine artery blood flow RI in patients with repeated implantation failure was positively correlated with MVD, which has clinical significance in predicting the outcome of embryo transfer.