I read a novel about a wet nurse who was one for YEARS. Like, her whole adult life. She was pregnant once, lost the baby (stillborn I think) but was able to nurse other babies the rest of her life, without getting pregnant or having sex. She was considered a savior in her town for nourishing people during a famine (this novel took place a looong time ago like the 14th century).
(inspired by this post)
Edit: I am stupid, bbsy is smart!