35 participants will be recruited from a list of patients who are scheduled, as part of their routine NHS care, to have a clinically-indicated outpatient hysteroscopy for assessment of their uterine cavity. The participants will be women from the age of 18 up to the age of 40 who are undergoing hysteroscopy investigation. All participants included in the study require at least one ultrasound scan, within the preceding 5 years, demonstrating the presence of a normal uterine cavity devoid of uterine anomalies such as a septate uterus or intrauterine fibroids (which may affect endometrial blood flow measurements). It is usual for a patients to have an ultrasound assessment prior to hysteroscopy therefore we do not anticipate this requirement limiting the number of eligible participants available.

Patient registry: Recruited patients will be registered on 'Edge', a secure, password-protected, database for study participants.

All the investigators will comply with the requirements of the GDPR 2018 with regards to the storage, processing and disclosure of personal information and will uphold the Act's core principles.

Access to patient-identifiable data will be restricted to the core patient-facing members of the research team at Birmingham Women's and Children's Hospital. The patient-facing members will be the Chief Investigator (ME), the Principal Investigator (JC), and co-investigator (HH).

The study involves depersonalised data and the data will be maintained within secure servers. The Birmingham Women's Hospital Research and Development department will hold an archived copy of the study data.

The Chief Investigator (ME) and the Principal Investigator (JC) will act as data custodians and keep the site file locked away securely with restricted access to study data for 25 years. Only the aforementioned members of the research team will have access to the site file for the purpose of quality control, audit and analysis.

Coded, depersonalised data will be created and used for study documents, in place of participant-identifying information. The participant data within the study and the code linking this data to the individual's true identity and identifiable data will be kept in separate locations using encrypted digital files within password-protected folders and storage media

Inclusion Criteria:

• Women from the age of 18 up to the age of 40 who have consented to hysteroscopy investigation as part of their standard NHS care.
• Women who have had an ultrasound scan, within the preceding 5 years, demonstrating a normal uterine cavity with no gross anatomical abnormalities (e.g. uterine septum).
• Women who have given informed consented to take part in the study

Exclusion Criteria:

• Inability to tolerate vaginal examinations
• Women who are pregnant
• Women who do not have regular menstrual cycles
• Women who have not given consent to the study.

Women from the age of 18 up to the age of 40 who have consented to hysteroscopy investigation as part of their standard NHS care.