Materials and Methods: In this single-blind randomized clinical trial, 60 infertile women with a history of at least one in vitro fertilization (IVF) cycle cancellation due to less than 7 mm endometrial thickness (ET) after receiving standard hormonal therapy were randomly assigned into two groups (n=30/each): the intervention group recived intrauterine injection of 5 mL exosome suspension on the 8th day of IVF cycle) and the control group received Intrauterine injection of 5 mL sterile water on the 8th day of IVF cycle). Demographic characteristics, pre- and post-treatment endometrioma size, pelvic pain, dysmenorrhea, and dyspareunia were compared in both groups.

Results: Baseline information has no significant differences between the two groups. Despite the significant increase in the ET following hormonal therapy in both groups, the number of women with ET less than 7 mm in the control group was about twice (13 vs. 6) that of the intervention group, resulting in cycle cancellation. Of the cases who enter the embryo transfer cycle, pregnancy was detected in 3 women (12.5%) in the intervention group and 1 case (6.6%) in the control group, with no significant difference between the groups (P = 0.612).

Conclusions: Finally, the results of the present study showed that although the use of MSCs can decrease the number of IVF cycle cancellations; however, larger studies is needed to confirm our findings.