Hey Jess!

We pay our mw out of pocket. There's a chance that with dh's new job the new insurance will pay for 10-80%. It's out of network maternity care and we have no out of network coverage so I'll need to write a letter. With pregnancy #1 we had an HMO that we knew wouldn't cover mw, but would cover my ob. So I used mw for prenatals and planned to birth at her birth center. Labs, scans and other prenatals we through ob. I paid mw each time I saw her (as I do now). I pay towards the 4k fee so I try and make the payments 100-300 bucks. With pregnancy #1 I had paid $350-400 when I pprom'ed. It was made very clear at that time that I didn't owe anything more and mw was by my side for about 12-20 hours (can't remember much so this is dh's guess) at the hospital as my doula. After I pprom'ed but before I was in the hospital dh and I spent some time at the birthcenter relaxing and trying to gather information/keep it together. MW does offer doula services and she charges $1000 for them.
I've heard other loss mamas get complete refunds from their mw's after even a loss during labor/at term.
I think it would depend on why you transfered. If you get tired and want an epi I'd imagine you'll get your mw as doula/labor support but will be paying the cost of your agreed amount. If you transfer because something goes wrong...decels or prom or something not scary persay but better handled in a hospital I
imagine you'll pay for your mw that agreed amount.
In any case I've heard of, all insurance that is supplying maternity services will cover a transfer and you'll pay the % or copay your policy has.
My mw seems to have mostly ppo clients that pay the normal 20-60% of her fee.