Doppler Evaluation of Uterine Blood Flow in Patients with Unexplained Recurrent Pregnancy Loss.

Objective: This study aimed to analyze uterine artery and spiral artery hemodynamics in patients with unexplained recurrent pregnancy loss (URPL) with varying pregnancy outcomes.

Methods: 174 pregnant women with URPL and 144 pregnant women without adverse pregnancy histories were enrolled in this retrospective study. Based on pregnancy outcomes, these patients were divided into two groups: normal pregnancy outcomes (URPL-N, n=138) and adverse pregnancy outcomes (URPL-A, n=36). Control group participants were categorized into normal pregnancy outcomes (CON-N, n=129) and adverse pregnancy outcomes (CON-A, n=15). We compared uterine artery and spiral artery hemodynamics during different stages of gestation and the predictive value of these parameters for pregnancy outcomes.

Results: URPL-N group had fewer pregnancy losses and lower BMI compared to URPL-A group (P< 0.05). Spiral artery hemodynamics in URPL-N and CON-N groups were lower than those in URPL-A and CON-A groups during the mid-luteal phase, 11-13 weeks, 15-17 weeks, and 19-21 weeks of gestation, respectively. Uterine artery hemodynamics ((Pulsatility index (mPI), resistive index (mRI), and systolic-to-diastolic ratio (mS/D)) in the mid-luteal period were lower in URPL-N group than URPL-A group. Similarly, in CON-N group were lower than CON-A group. The URPL-A and CON-A groups had higher uterine artery and spiral artery hemodynamics when compared to the URPL-N and CON-N groups. Spiral artery hemodynamics exhibited larger areas under the ROC curve compared to uterine artery parameters.

Conclusion: Abnormal hemodynamics in these arteries may contribute to URPL and adverse pregnancy outcomes. Spiral artery hemodynamics are more reliable predictors of pregnancy outcomes than uterine artery parameters.