He replied:

Yes. If she experiences the usual menstrual bleeding, she counts it towards her waiting period. Likewise, if she takes medicine that stops menstruation or lengthens the interval between periods, that interval counts as a period of purity. The same applies if hunger, fatigue, or other causes that warm her constitution and stir the blood bring on menstruation. And Allah knows best.

He—may Allah have mercy on him—was asked:

A woman whose hair had turned grey, but who had not reached menopause, used to menstruate regularly. She took medicine, whereupon her bleeding stopped and remained absent. Her husband then divorced her while she was in this condition. Is her waiting period to be calculated in months from the time of divorce, or must she wait until she reaches menopause?

He replied:

All praise is due to Allah, Lord of all worlds. If she knows that her bleeding will [not] (1) return, her waiting period is three months. If it may or may not return, she should wait until a year has passed and then marry, as ‘Umar ibn al-Khattāb ruled concerning a woman whose menstruation ceases without her knowing what caused it: she should wait a year. This is the position of the majority, including Mālik and al-Shāfi‘ī.

As for the view that she must reach menopause, it is very weak indeed, quite apart from the harm it entails—harm of a kind the Sharia does not prescribe. Or should she be prevented from marrying when she needs to, only to be permitted to marry when she no longer needs to?