Ḥayḍ terminates when a woman reaches the age of menopause.
Age of “losing hope” for Ḥayḍ and Nifās (i.e., Menopausal Age)

Lunar: 55 years. [Preferred Opinion]
Solar: 53 years 4 months.
Rule 1: When a woman reaches the age of 55 and her bleeding stops, the judgement of her being in menopause is passed.
Rule 2: The ʿiddah (for a divorce) of a woman who reaches the age of 55 and is no longer seeing blood is counted as 3 lunar months.