Nothing. I had all three of my children without drugs of any kind.
I highly recommend classes (Lamaze, Bradley, etcetera) which can help you learn how to manage through the pain so you will be able to deliver without resorting to medications.
But I also believe it is each woman's right to medicate if she feels it is necessary. Just be sure to educate yourself on the possible effect such drugs may have on your labor and delivery, as well as on your baby.
Good luck.