Pregnancy outcomes in oocyte recipients with fibroids not impinging uterine cavity

Objective: To examine the effects of fibroid uterus on pregnancy outcomes and endometrial features in ovum donation recipients. Methods: Retrospective analysis of 744 ovum donation cycles was conducted in two private IVF centers between 2005 and 2012. All the recipients underwent transvaginal ultrasound examination, including endometrial thickness and grade measurements. Clinical pregnancy, spontaneous miscarriage, and live birth rates were regarded as the primary outcomes. Results: Leimyomas not distorting the uterine cavity were diagnosed in 264 (35.5%) of the cycles. This group exhibited lower endometrial thickness (8.33 ± 1.8 vs. 8.73 ± 2.03 mm, p = 0.009), lower rates of Grade A (16.1 vs. 30.1%, p < 0.0001), and higher rates of grade C endometrium (10.2 vs. 5.5%, p < 0.0001), compared to the group with sonographically normal uterine cavity. In addition, significantly higher spontaneous miscarriage rates were found in fibroid uteri group (25 vs. 14.5%, p = 0.036). Conclusion: Our study results suggest that uterine fibroids not distorting the uterine cavity could constitute a risk factor for spontaneous miscarriage in oocyte donation cycles, possibly via their adverse effect on endometrial receptivity. Further well-designed trials should widely explore this subject, particularly focusing on impact of myomectomy on fertility rates in these patients.