Yanyu Zhong,1,* Nan Wang,1,* Sihui Lu,2 Yaqian Lu,2 Xin Pan,3 Ying Zhou1 

1Reproductive Medicine Centre, The First Affiliated Hospital of Soochow University, Suzhou, People’s Republic of China; 2Department of Obstetrics and Gynecology, The Fourth Affiliated Hospital of Soochow University, Suzhou, People’s Republic of China; 3Department of Obstetrics and Gynecology, The First Affiliated Hospital of Soochow University, Suzhou, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Ying Zhou, Reproductive Medicine Centre, The First Affiliated Hospital of Soochow University, No. 899 Pinghai Road, Gusu District, Suzhou, Jiangsu Province, 215008, People’s Republic of China, Tel +86-0512-67973182, Email zhouyingzzzyyy@163.com Xin Pan, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Soochow University, No. 899 Pinghai Road, Gusu District, Suzhou, Jiangsu Province, 215008, People’s Republic of China, Tel +86-0512-67973182, Email panxinxin9@outlook.com

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.

Keywords: unexplained recurrent pregnancy loss, spiral artery, uterine artery, blood flow, pregnancy outcome