In 2018, 141.4 million working days were lost because of illness or injury in the UK, with minor illnesses such as colds and coughs being the most commonly cited reason for days lost, accounting for 27.2% (38.5 million days) of all days lost. However, influence of fluctuations in oestrogen and progesterone across the menstrual cycle on mucosal immunity are yet to be examined in a rigorous study, which controls for menstrual phase and contraceptive use, and confirms ovulatory cycles, The aim of this study is to determine the influence of the menstrual cycle on mucosal immunity. We will use a rigorous observational design, which controls for sleep, nutrition, psychological stress, circadian rhythm, menstrual cycle phase and contraceptive use, measures reproductive hormones to verify cycle phase, confirms ovulatory cycles, and is adequately powered to account for large inter- and intra-individual variation in oestrogen and progesterone.

Funding awarded through the Bangor University Innovation and Impact Award (Research Wales Innovation Funding). Value = £16,873