The waiting period for a woman who does not menstruate, whether prepubescent or postmenopausal, is three months.
If a woman normally menstruates, but her periods have stopped for some reaSOn such as breastfeeding or the like, or without apparent reason, then she must wait until the age of menopause, after which her waiting period is three months. (N: In the Maliki school, such a woman must wait nine months, and if neither pregnancy nor menses appear, she is considered to be as if menopausal, and her waiting period is three more months, making a total of one entire year in which there is no menstrual flow.) - Fiqh Umdat n9.9 (islam)