Are you going to be doing obstetrics, and if so, are you willing to back up midwives doing deliveries?

This answer is simple if you don't plan on doing deliveries. If you do, midwifery home births and natural childbirth are constantly in vogue within varying percentages of a hospital's demographics. When you appreciate that the only reason you'd become involved is when a serious problem came up, you will realize that being a part of this scheme means you'll dodge the liability (and rightfully so), by having the patient cared for by an obstetrician or maternal fetal specialist. This shouldn't bother you if it's part of the hospital service, but home deliveries are a different liability altogether. You should state that the very nature of referral from a midwife means a specialist in obstetrics is needed. Not you.