Abnormal ultrasound typically requires further investigation including endometrial biopsy (sampling). The evidence is solid that endometrial sampling may result in discomfort, bleeding, infection, and rarely uterine perforation. A study designed to evaluate performance, patient acceptance, and cost-effectiveness of blind biopsy, hysteroscopy with biopsy, and ultrasound, in 683 women with vaginal bleeding, reported that minor events, including discomfort and distress, occurred in 16% of women who had hysteroscopy with biopsy, and in 10% of the women who had a blind biopsy.[1] A group of researchers studied 13,600 diagnostic and operative hysteroscopic procedures and found a lower complication rate among diagnostic procedures (0.13%) compared with operative procedures (0.28%).[2] Risks associated with false-positive test results include anxiety and additional diagnostic testing and surgery. Endometrial cancers may be missed on endometrial sampling and ultrasound.

References

1. Critchley HO, Warner P, Lee AJ, et al.: Evaluation of abnormal uterine bleeding: comparison of three outpatient procedures within cohorts defined by age and menopausal status. Health Technol Assess 8 (34): iii-iv, 1-139, 2004.  [PUBMED Abstract]
   
   
2. Jansen FW, Vredevoogd CB, van Ulzen K, et al.: Complications of hysteroscopy: a prospective, multicenter study. Obstet Gynecol 96 (2): 266-70, 2000.  [PUBMED Abstract]