Evaluation of ChatGPT, Gemini, and OpenEvidence in Obstetric and Gynecologic Clinical Decision Scenarios.

Background Clinicians frequently face questions that require rapid, evidence-based answers. Artificial intelligence (AI) tools are increasingly used for this purpose, yet their reliability for clinical decision-making remains uncertain. This study compared two generative large language model (LLM) systems (ChatGPT and Gemini) and a retrieval-supported clinical platform (OpenEvidence) to determine which provides the most reliable, clear, and clinically applicable information in obstetrics, gynecology, and urogynecology. Methods A cross-sectional comparative design was used to evaluate ChatGPT (GPT-5), Gemini (Gemini 2.5), and the retrieval-supported platform OpenEvidence. Twenty-four clinical questions across three subspecialties were independently assessed by two blinded specialists using the Expert-Adapted DISCERN (EA-DISCERN) tool, which rates 12 quality domains on a five-point scale. Mean ± SD scores were compared across systems and clinical domains using repeated-measures analysis. Results OpenEvidence achieved the highest mean total score (54.0 ± 2.3), outperforming Gemini (50.3 ± 2.4) and ChatGPT (48.7 ± 2.4) (p < 0.001). OpenEvidence scored significantly higher in evidence-based domains; clinical accuracy, guideline consistency, completeness, transparency, and reliability across all fields. As of this writing, Gemini ranked between the two, showing a modest advantage over ChatGPT in rationale explanation and evidence transparency, while both generative models scored higher in language fluency and readability. Overall, total EA-DISCERN scores ranked OpenEvidence highest, followed by Gemini, then ChatGPT. Inter-rater reliability for the total score was ICC[2,1] (absolute agreement = 0.391). Conclusions OpenEvidence provided more guideline-aligned and transparent responses, whereas ChatGPT and Gemini were generally more fluent and readable. For OB/GYN clinicians, retrieval-supported platforms may be more suitable for point-of-care verification, while generative models should be used more cautiously and with clinician oversight.