Comparative study to determine whether several fertility monitoring products - the DuoFertility monitor, the LadyComp/Babycomp monitor and Clearblue Ovulation tests - are substantially equivalent in performance, and secondarily to determine the appropriateness of labeling information for the DuoFertility monitor.

The investigators plan to recruit 30 women who are currently trying to conceive, and ask them to use the 3 fertility monitors for duration of 3 menstrual cycles. Additionally, during the study the women will be asked to fill in online questionnaires to assess the usability of the monitors. As the spouse is often a critical partner in the purchase decision and compliance, the investigators will also ask the spouse to complete similar online questionnaires.

Inclusion Criteria:

• Participant is willing and able to give informed consent for participation
• Females aged 18 to 44 years
• Have a body mass index (BMI) above 19 and below 29
• Regular menstrual cycles, i.e. no greater than 7 days difference between the shortest and longest cycle in the last 6 months
• Minimum menstrual cycle 24 days
• Maximum menstrual cycle 33 days
• Female participants willing to use the 3 fertility monitors for at least 3 cycles.
• Willing to fill in regular questionnaires and study diaries

Exclusion Criteria:

• Women aged younger than 18 years, or older than 44 years
• Have a BMI less than 18 or greater than 29
• Any diagnosed systemic illnesses, including but not restricted to thyroid disease, diabetes or inflammatory diseases
• Polycystic ovary disease
• Endometriosis or other pelvic pathology (including proven tubal disease)
• Taking steroids, including oral contraceptives or anti inflammatory drugs

Female participants trying to conceive, with regular menstrual cycles.