Although the various physical causes of the menopause are well documented (see Wikipedia), from an evolutionary perspective the reasons for its prevalence in humans are unknown -(only two other mammals are known to exhibit menopause, see note below.)
“Menopause is an evolutionary puzzle since an early end to reproduction seems contrary to maximising Darwinian fitness.” source
Note : The only other mammals which are known to show menopause are orcas and short-finned pilot whales.
More details BBC, Aug 2016
“From an evolutionary perspective, it's very difficult to explain,”