Has anyone's baby been born in the amniotic sac?

No real reason I'm asking but when I was in labor with my son they didn't break my water until about half an hour before delivery(Probably 8-9 cm). Just wondering if any woman did delivery their children while still in the sac? I kinda think my son would have been born in his if they didn't break my water, and I know it's just a superstition and I don't believe it but I've always heard babies born within their amniotic sac are "good luck babies" lol Any woman had their babies born in the sac? And how did it differ from a baby born outside of the sac?