Alterations of Uterine Blood Flow During the Follicular Phase in Patients With Recurrent Implantation Failure: A Doppler Ultrasonographic Study

Objectives: The dynamics of blood flow in the endometrium plays a crucial role during the implantation process. This study aimed to assess the uterine perfusion during the follicular phase in patients with a history of recurrent implantation failure (RIF) and healthy fertile women using the transvaginal ultrasound color Doppler method. Materials and Methods: To this end, 50 patients with RIF and 50 age-matched healthy fertile women were recruited in this case-control study. The transvaginal color Doppler ultrasonography was used to evaluate the pulsatility index (PI) and resistance index (RI) of the uterine, arcuate, and sub-endometrial arteries during the follicular phase in both groups. Results: The RI and PI of both right and left uterine arteries were higher in the RIF group compared to the fertile women (P<0.05). Our results showed that the PI and RI of sub-endometrial blood flow and the RI of arcuate arteries were substantially higher in the group with a history of RIF in comparison with the control group. However, the PI of arcuate arteries was not significantly different between the groups. Conclusions: Adequate uterine perfusion and sub-endometrial blood flow are necessary to achieve successful implantation and pregnancy since our results demonstrated the higher resistance of uterine and sub-endometrial arteries in patients with a history of RIF. Thus, the assessments of uterine perfusion indices during the follicular phase could be used as a non-invasive method in the evaluation of patients with RIF.