Measurement of luteinizing hormone surge in vaginal discharge: a potential biomarker that enables simple, non-invasive prediction of the periovulatory period.

"Declarations Ethics approval and consent to participateThe study was conducted with approval from the Research Ethics Committee of Kyoto College of Nursing, Japan (ref. no.: 201905). Informed consent was obtained form all the participants. All research assistants who provided the participants with an explanation of the study were all women registered midwives certified in Japan, which we felt was important to ease participants’ concerns about sending samples of their urine and VD samples to. The participants were permitted to skip the sample collection and withdraw from the study at any time without any disadvantage to themselves. All methods were carried out in accordance with relevant guidelines and regulations. The study team consulted the World Health Organization’s guidelines for sample submission via mail before implementation of the study. Given the time-consuming and unusual nature of the study, the participants received a financial incentive in an amount approved by the Research Ethics Committee, depending on the number of samples submitted. All data and samples were anonymized by the assignment of ID numbers encoding the subject and type of sample. Consent for publicationNot applicable. Competing interestsThe authors declare no competing interests. Competing interests The authors declare no competing interests."

"Funding This study was supported by a joint research project between Kyoto College of Nursing and Cellspect Co. Ltd."