What is the best supplimental insurance for pregnancies?

My wife already has insurance that has a high deductible for pregnancies. I'm trying to find a good supplimental insurance program (i.e. aflac., etc) specifically for expecting mothers or mothers who plan on having children. Any good suggestions? My wife and I are planning on having children (so we are not pregnant yet) but we are looking into how to pay for the pregnancy. My wife already has insurance that has a high deductible for pregnancies. I'm trying to find a good supplimental insurance program (i.e. aflac., etc) specifically for expecting mothers or mothers who plan on having children. Any good suggestions