Sonographic and hysteroscopic endometrial examination in women treated with ulipristal acetate: Exploratory findings at a tertiary referral center.

OBJECTIVE: Ulipristal acetate (UPA) is a progesterone receptor modulator (PRM) agent that has shown benefits in women with symptomatic uterine fibroids. However, its effects on the endometrium are complex and not fully understood. We describe exploratory findings on macroscopic observation of the endometrium at transvaginal sonography (TVS) and hysteroscopy. The aim of the study is to characterize endometrial patterns commonly observed after UPA treatment.

STUDY DESIGN: We performed a prospective longitudinal study at a tertiary referral center with 100 women with symptomatic uterine fibroids who received a 12-week treatment with UPA (5 mg/day). Patients underwent TVS before and after the treatment, and also a hysteroscopy examination was performed. Main outcome was to compare sonographic and hysteroscopic findings to histology after UPA treatment.

RESULTS: Twenty one out of 100 (21%) women showed PAEC confirmed by histology after UPA treatment. Ultrasound findings were normal in most women after UPA treatment, but 18/100 (18%) showed an endometrial pattern suggestive of PRM effects (non-uniform, homogeneous endometrium with regular cystic areas). Endometrial thickness ≥16 mm was detected in 6/100 patients (6%), and all of them also presented sonographic PRM pattern. No patient presented malignancy according to histology in this subgroup, and 100% of them had PAEC pattern at histology. Among total patient population showing PAEC at histology, only 33% of these were identified by hysteroscopy, while 57% were identified by TVS with the PRM suggestive pattern. Of note, visibility of endometrium was improved at TVS after UPA.

CONCLUSION: Identification of increased endometrial thickness together with the categorized endometrial PRM pattern at TVS may be correlated to benign lesions and may not be a cause of concern. This study is exploratory and further research is necessary to support these conclusions. Nevertheless, TVS seems to be feasible to plan adequate follow-up protocols by avoiding unnecessary interventional procedures such as hysteroscopy.