Why should women stay away during menstrual cycle for five days?Please give me if any scientific reasons?

Menstrual cycle in a women is just normal biological or metabolic process .I just want to know how does this effect or make a women impure or a non- auspicious object for that five days.Any scientific reasons for that?I am sure that there would be definetely valid reasons for our elders practises but i want to have clear view like what not to do and how to lead normal day to day life during those five days as i hear many different conditiond from different people to follow during those five days.i get frustated and confused tooo often.so pls guide me . I was told that women should not cook ,should not wlak freely inhome ,shold sit at one corner of house,should not touch others etc.Please tell me If theres any books to clear these doubts of mine .