Effects of the Distance between Small Intramural Uterine Fibroids and the Endometrium on the Pregnancy Outcomes of in Vitro Fertilization-Embryo Transfer

To explore the effects of the distance between small intramural uterine fibroids (≤4 cm) and the endometrium on the outcomes of in vitro fertilization-embryo transfer (IVF-ET).We prospectively analyzed pregnancy outcomes in 117 infertile women with small intramural uterine fibroids and 117 infertile women without uterine fibroids who all underwent IVF-ET. The size and number of small intramural uterine fibroids and the shortest distance between the small intramural uterine fibroids and the endometrium were measured by transvaginal three-dimensional ultrasound. The endometrial and subendometrial blood flow parameters, implantation rate, clinical pregnancy rate, abortion rate and live birth rate were compared between the women with and without small uterine fibroids and among the different shortest distances (≤1, 1-3 and >3 mm). The effects of the size and number of small intramural uterine fibroids on IVF-ET outcomes were observed.The endometrial volume on ET day, the implantation rate and the live birth rate were significantly lower, but the abortion rate was significantly higher, in the women with small intramural uterine fibroids than in those without uterine fibroids (p < 0.05). The endometrial flow index was higher in the shortest distance ≤1-mm group than in the groups with 1-3 and >3 mm, and the implantation rate was higher in ≤1-mm group than in the >3-mm group (p < 0.05). There were no significant differences in clinical outcomes between different sizes and numbers of small intramural uterine fibroids.Small intramural uterine fibroids can affect IVF-ET outcomes. Compared with other shortest distances (1-3 and >3 mm), the shortest distance of ≤1 mm has a higher implantation rate.