A retrospective observational study of changes in uterine fibroid blood flow and fibroid diameter after administration of gonadotropin-releasing hormone agonists and antagonists using superb microvascular imaging.

AIM: The relationship between the changes in fibroid blood flow and fibroid diameter during the administration of GnRH agonists and antagonists was examined using superb microvascular imaging (SMI).

METHODS

Changes in the maximum fibroid blood flow and diameter at weeks 0, 2, 4, and 8 were compared between the relugolix, a GnRH antagonist, and leuprolide, a GnRH agonist, groups.

RESULTS

Data were collected for 16 fibroids from 12 patients in the relugolix group and 12 fibroids from 9 patients in the leuprorelin group. A significant decrease was observed in the fibroid diameter at 8 weeks in the relugolix group, but no significant change was observed at any time point in the leuprorelin group. In the relugolix group, a significant correlation were observed between changes in blood flow at 2 weeks and fibroid diameter changes at 2 and 4 weeks, and between changes in blood flow at 4 weeks and fibroid diameter changes at 4 weeks. No significant correlation was observed in the leuprorelin group.

CONCLUSION

In the treatment of uterine fibroids with relugolix, a reduction in fibroid blood flow assessed by SMI may suggest a subsequent reduction in fibroid size. These results provide useful insights when making the decision whether or not to continue relugolix administration.