In the UK and US . nearly all twins are born by caesarean surgery. Often, this is because of the positioning of the first twin. If the first twin is not head down, most doctors routinely deliver surgically. However, if you are adamant about a vaginal delivery, you should be clear with your doctor or midwife and discuss any potential risk associated with your decision. You should also check  with your doctor or midwife to see how much experience they have delivering multiples vaginally, and under which conditions they would not be willing to deliver vaginally.