Umbilical cord...

So I haven't experienced this yet. And am needing advice. I was told the other day at an US that babies cord was behind his neck. He is already head down at 30 weeks almost 31 weeks. They said cord is in a danger zone but hasn't wrapped around neck but has a higher chance of doing so... now let's say it does end up wrapping around. Who has given birth vaginally with this problem? And what was the method your doctor used to help baby and you with this issue during delivery?