vaginal birth or c-section with twins?

IVF won't affect it. It just depends on how the babies are positioned when its time, but that's the same with any pregnancy! :) good luck!

Correct, if both babies are are head down, then many Obs may allow you to deliver vaginally. Everything else many may elect to do a C/S.. The only other exception is if the lead baby is head down, with the other breech... but this would definately depend on the obstetrician

IVF or any fertility treatments doesn't impact this