Is it possible to lactate into old age?

No it is not possible to lactate into old age. Hormones levels begin to drop significantly around the mid to late 40s. This drop means no ovulation, no periods, no chance of pregnancy,and thus, no possibility of lactation. You may have heard women or physicians/nurses refer to "old eggs" and in a sense, this becomes very true in peri-menopause. In post-menopause, "eggs", "ovulation", pregnancy and lactation cease to exist.

If a woman who is post menopause begins bleeding or having breast discharge (not lactation even if the fluid might look similar), she should see her doctor (sooner rather than later).