Contrast media for hysterosalpingography: systematic search and review providing new guidelines by the Contrast Media Safety Committee of the European Society of Urogenital Radiology

Objectives: Hysterosalpingography (HSG) is widely used for evaluating the fallopian tubes; however, controversies regarding the use of water- or oil-based iodine-based contrast media (CM) remain. The aim of this work was (1) to discuss reported pregnancy rates related to the CM type used, (2) to validate the used CM in published literature, (3) to discuss possible complications and side effects of CM in HSG, and (4) to develop guidelines on the use of oil-based CM in HSG. Methods: A systematic literature search was conducted for original RCT studies or review/meta-analyses on using water-based and oil-based CM in HSG with fertility outcomes and complications. Nine randomized controlled trials (RCTs) and 10 reviews/meta-analyses were analyzed. Grading of the literature was performed based on the Oxford Centre for Evidence-Based Medicine (OCEBM) 2011 classification. Results: An approximately 10% higher pregnancy rate is reported for oil-based CM. Side effects are rare, but oil-based CM have potentially more side effects on the maternal thyroid function and the peritoneum. Conclusions: 1. HSG with oil-based CM gives approximately 10% higher pregnancy rates. 2. External validity is limited, as in five of nine RCTs, the CM used is no longer on the market. 3. Oil-based CM have potentially more side effects on the maternal thyroid function and on the peritoneum. 4. Guideline: Maternal thyroid function should be tested before HSG with oil-based CM and monitored for 6 months after. Clinical relevance statement: Oil-based CM is associated with an approximately 10% higher chance of pregnancy compared to water-based CM after HSG. Although side effects are rare, higher iodine concentration and slower clearance of oil-based CM may induce maternal thyroid function disturbance and peritoneal inflammation and granuloma formation. Key Points: • It is unknown which type of contrast medium, oil-based or water-based, is the optimal for HSG. • Oil-based contrast media give a 10% higher chance of pregnancy after HSG, compared to water-based contrast media. • From the safety perspective, oil-based CM can cause thyroid dysfunction and an intra-abdominal inflammatory response in the patient.