You would have to talk to your doctor about that because we wouldn't know the risks associated with a cyst that large in a baby's abdomen and if the stress of a vaginal birth would cause any issues.
Take your concerns to your doctor! A natural, low or no medicine birth might be ideal if you are allowed to go vaginally as an epidural increases the risks of needing an emergency c-section. When you get an epidural they most always hook you up to Pitocin or a similar synthetic hormone because the epidural causes your contractions to slow down. Pitocin causes you to have stronger but less effective contractions but at least gets your uterus contracting.
So if you can avoid an epidural and Pitocin you have less risk of putting the baby through Pitocin distress. Also laying on your back in the bed reduces the oxygen getting to baby which also causes distress; getting up and moving or leaning over the bed swaying will increase your chances of having a natural, vaginal birth and for most women decreases labor time.
Again, talk to your doctor about your concerns and desire to give birth vaginally.
that's a decision that you, your husband and doctor need to make together. You all need to sit down at your next appointment and discuss the risk and benefits of each del. type to you and your baby. Plus you need to find out from your doctor if there is any need at all to be worried about how you del. your child because of this cyst there may be no need to be concerned as far as how you have the baby.
Really the best thing is for all three you to talk about it