Hysterosalpingogram (HSG)

By RRM Academy Reviewed by Dr. Naomi Whittaker, MD, Board-Certified OBGYN, MIGS, NFPMC, FCI Updated July 27, 2026

A hysterosalpingogram (HSG) is a radiographic procedure in which the clinician injects radiopaque contrast dye through the cervix into the uterine cavity and fallopian tubes under fluoroscopic X-ray guidance.¹ The HSG test produces a real-time image of uterine cavity shape and tubal patency.² HSG is one of the most common tubal patency tests used in fertility evaluation.³ HSG reveals filling defects and cavity contour abnormalities suggestive of intracavitary lesions such as polyps, submucosal fibroids, and adhesions.⁴ HSG reveals uterine septal defects.⁵ HSG reveals proximal or distal tubal obstruction.⁶ Definitive characterization of intracavitary lesions often requires hysteroscopy, 3D ultrasound, or saline sonography.⁴ MRI is reserved for characterizing complex Mullerian anomalies when 3D ultrasound findings are inconclusive; 3D ultrasound is now the preferred modality for most uterine septal defects.⁵

The HSG procedure does have limits. False-positive tubal occlusion from tubal spasm occurs with HSG.⁶ HSG opacifies only the uterine cavity and tubal lumen, so peritoneal endometriosis and pelvic adhesions fall outside its diagnostic field of view and require laparoscopy to assess.⁶ A couple's full picture requires more than a dye study.

Does the HSG itself improve fertility? Clinicians have long observed that some couples conceive in the months following an HSG, particularly when oil-based contrast is used.⁷ Randomized evidence has reported higher pregnancy rates after an oil-based contrast HSG compared with water-based contrast; the mechanism of the fertility-enhancing effect of oil-based contrast HSG is not established.⁸ Proposed explanations for the fertility-enhancing effect of oil-based contrast include immunological effects of iodized oil, mechanical clearance, and surfactant action.⁹ The HSG is performed to find the structural cause, and this added benefit does not substitute for a cause-based evaluation of why conception has not yet occurred.

In a cause-based evaluation, HSG is often an early step in assessing tubal structure.³ HSG may be followed by diagnostic laparoscopy for definitive assessment of pelvic pathology.¹⁰ When proximal tubal obstruction appears on standard HSG, the next step is to determine whether the block is real or an artifact of tubal spasm. Selective salpingography places a catheter at a single tubal ostium to image that tube in isolation, confirming a true mechanical occlusion versus a spasm-induced false positive.¹¹ When a true partial proximal block is confirmed, transcervical catheterization of the fallopian tubes advances a catheter-guidewire through the obstruction to recanalize it, often in the same session, without open surgery.

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.