Saline Infusion Sonohysterogram (SIS) / "Bubble Test"

By RRM Academy Reviewed by Dr. Naomi Whittaker, MD, Board-Certified OBGYN, MIGS, NFPMC, FCI Updated May 7, 2026

A transvaginal ultrasound performed while infusing sterile saline into the uterine cavity, providing enhanced visualization of the endometrial cavity and uterine walls. SIS is the primary diagnostic tool for uterine isthmocele, enabling measurement of the defect dimensions and residual myometrial thickness. It also detects endometrial polyps, submucosal fibroids, intrauterine adhesions, and uterine septa, and can assess tubal patency.¹⁵¹⁶

This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.