The goal of this clinical trial is to assess the use of inhaled nitrous oxide during office hysteroscopy.

The main questions it aims to answer are:

• Does it reduce pain during the procedure?
• Does it increase the success rate?
• Does it improve patient satisfaction?
• Does it reduce anxiety?
• Which populations benefit more (e.g., parity, menopausal status, number of previous surgeries, type and duration of procedure, and type of device)?

Participants will be asked about their pain levels during the procedure, as well as their anxiety levels. All responses will be recorded.

Written informed consent will be obtained prior to initiation.

Office hysteroscopy offers a convenient alternative to operating room-based procedures, yet many patients experience pain and anxiety significant enough to interfere with procedural completion. Nitrous oxide is a fast-acting inhaled agent with both analgesic and anxiolytic properties, widely used in outpatient settings across various medical specialties.

This study will investigate the role of nitrous oxide in improving patient tolerability and comfort during office hysteroscopy. Participants will undergo a standardized procedural protocol with either nitrous oxide or ambient air administered via a demand-valve mask system. Comprehensive data on patient responses during the procedure will be collected and analyzed.

The study will also examine variability in patient responses across different subgroups and procedural types. All procedures will adhere to ethical standards, and patient confidentiality will be maintained throughout.

Inclusion Criteria:

Women aged ≥18 years Scheduled to undergo operative office hysteroscopy for clinical indications

Exclusion Criteria:

Any contraindications to N₂O, including:

Pneumothorax Significant chronic obstructive pulmonary disease (COPD) Upper airway obstruction Bowel obstruction Middle ear pathology (e.g., recent ear surgery or active ear infection) Severe recent intraocular gas injection Severe vitamin B12 deficiency Known hypersensitivity to N₂O

Women who will decline randomization or unable to provide informed consent.

Self-identified females assigned female at birth are eligible to participate.

De-identified individual participant data (IPD), including pain scores, anxiety scores, demographic characteristics, and procedural outcomes, will be made publicly available through an open-access data repository (e.g., Zenodo) at the time of primary results publication.

The data will be freely accessible for academic and research use, with no restrictions or approval required.

De-identified individual participant data (IPD) and supporting information will be made publicly available at the time of primary results publication in a peer-reviewed journal.

The data will remain accessible indefinitely via an open-access online repository.

The IPD and supporting documents will be accessible to all users via open access. No request or approval will be required.

A direct link to the data repository (e.g., Figshare, Zenodo) will be provided in the publication.