As an employee, you are protected from being treated less favourably because of your age. If you are treated less favourably because you’re going through the menopause, it could give rise to an age discrimination claim, given that menopause usually begins within a certain age bracket.
This may also be relevant to younger employees, who may go through medical or early menopause. An example of age discrimination could be if your fellow employees make fun of young people who go through the menopause.