My fiancé is really interested in using a mid wife for our pregnancy. What are the trade offs for using a midwife versus a traditional obgyn.

Varies. In one of my 2 hospitals nurse/midwives practice with a obgyn group and admit their patients into rooms side by side. When a problem arises, which will in 10% or more of labors, they have immediate access to OB backup. In such a setting, safety for mom and baby is assured. Those that promote home births, loose part of that safety factor. Those that do accept the risk.I discourage it.