Question

Why ovaries not produce estrogen reason

Answer 1

In addition to their role in producing ova, the ovaries also have the distinction of being an endocrine gland because they secrete hormones—primarily estrogen and progesterone—that are vital to normal reproductive development and fertility.
What causes ovaries to stop producing estrogen?

Premature menopause. ... Treatments such a radiation or chemotherapy can also cause induced menopause. Premature ovarian failure: A woman's ovaries produce progesterone and estrogen. The levels of these two hormones can change if the ovaries stop releasing eggs prematurely.