Allianz UK covers 100% as well with a ten month waiting period. My Bupa policy covers ?4,000 per annum for a normal delivery so if I fall pregnant in the last three quarters of the year I will be entitled to ?8,000 all up! If I need an emergency cesearian, or any acute complication then the gloves are off and they will pay EVERYTHING!!!! William Russell and Morgan Price are another two good UK based insurers. I've forgotten which is which but one is the standard ?4000 while the other covers ?5,000 with no waiting period as long as you weren't pregnant when you joined and provided you pay for your first ?1,000 of costs!
I found out about all of these policies through Medibroker so I really suggest you contact them. The broker that Rani mentioned has said on this forum that all my information is wrong but I had all the brochures and all the terms and conditions. UK co's really are a lot better and I know BUPA will cover non-emergeny medicial care in the US but you will have to pay a premium (emergency care is covered).