Effect of Low-Dose Aspirin on Midluteal Phase Uterine Artery Blood Flow in Patients With Recurrent Pregnancy Loss

Objectives-The purpose of this study was to evaluate differences in uterine artery blood flow parameters and pregnancy outcomes, if any. An investigation was conducted to determine the effects of low-dose aspirin on uterine artery blood flow indices in patients with recurrent pregnancy loss. Methods-This observational study included 353 Chinese women with a history of recurrent pregnancy loss and 85 women without a history of recurrent pregnancy loss (control group) from Ren Ji Hospital. All patients were scanned transvaginally with transvaginal Doppler sonography 6 to 8 days after ovulation to measure the pulsatility index (PI), resistive index (RI), and systolic-to-diastolic ratio (S/D) of the left and right main uterine arteries. Low-dose aspirin at a dose of 50 mg/d was administered orally in patients with recurrent pregnancy loss for 2 months, and the blood flow indices were measured subsequently. The Student t test was used for analysis of the results, P<.05 was considered significant. Results-The mean PI and S/D of the uterine arteries in the recurrent pregnancy loss group were significantly higher than in the control group. Although not statistically significant, the RI was higher in the recurrent pregnancy loss group than the control group. Moreover, the PI and S/D increased as the number of pregnancy losses increased. Significant enhancements of the PI and S/D were observed in patients with 4 or more consecutive abortions. After low-dose aspirin supplementation, patients with recurrent pregnancy loss showed a highly significant reduction in the PI and S/D. Conclusions-Uterine blood flow decreased during the luteal phase in patients with recurrent pregnancy loss. Low-dose aspirin induced a reversible increase in uterine blood flow and may be of therapeutic value.