Hard to say. I've read reports of at least three teenagers dropping dead after taking RU-486, the best known story being a girl in California whose parents were not informed what their daughter was doing.
The abortion industry and the left wing press will cover this up.
I'm not saying that thousands of people will die. But it's clearly dangerous to interfere with a woman's reproductive system and hormonal balances. At least some users will die, and if were happening with some non-abortion-related drug we'd be hearing a lot more about it. But the MSM can be relied on to cover it up, and the Labour Government and National Health Services, too.
This isn't about RU-486.