Methylene Blue Chromohysteroscopy as an Adjunct to Diagnostic Hysteroscopy in Women with Abnormal Uterine Bleeding: A Narrative Review

Abstract

Background: Abnormal uterine bleeding (AUB) is one of the most frequent reasons women seek gynecological care and can seriously affect daily life, work, and wellbeing. Conventional hysteroscopy is widely used to evaluate the uterine cavity, but subtle inflammatory, premalignant, or microscopic changes may be missed when the endometrium looks normal on white light. Methylene blue chromohysteroscopy has been introduced to make these subtle areas more visible and to guide more accurate biopsies.

Methods: This systematic review followed PRISMA 2020 guidance and used a PICO-based research question. We included women undergoing diagnostic hysteroscopy for AUB in whom methylene blue chromohysteroscopy was used as an adjunct to conventional hysteroscopy and compared with white‑light hysteroscopy alone, using histopathology as the reference where available. We searched PubMed/MEDLINE, Scopus, Cochrane Library, and Embase (January 2019–March 2025) and included randomized and non‑randomized studies, systematic reviews, and guidelines. Study quality and certainty of evidence were assessed using standard tools.

Results: Thirty‑five studies were included. Most showed that dark or focal methylene blue staining reliably highlighted areas with chronic endometritis, endometrial hyperplasia, or early malignancy, and improved the yield of targeted biopsy compared with conventional hysteroscopy or blind sampling. Several studies reported higher sensitivity and specificity with chromohysteroscopy, though a few did not demonstrate a clear additional benefit.

Conclusion: Methylene blue chromohysteroscopy appears to be a simple, low‑cost, and safe add‑on to standard hysteroscopy that helps uncover otherwise hidden endometrial disease. It should currently be viewed as a useful adjunct rather than a replacement for conventional hysteroscopy and histopathology, with further multicentre trials needed to define its routine role.