Its good to start thinking about what options you have well ahead of time because then you can put a policy in place if thats the route you choose. Here at Neighbourhood Midwives, we have worked with a few different private health companies now including Bupa international, Allianz Global Assistance and Simply Health and I think it's becoming more common for the more comprehensive policies to cover private midwifery care without the need for 'complications' to trigger payment.
You may be able to pay for a 'top up' to an ordinary policy too. Midwifery care is much cheaper than private obstetric care and offers continuity of care, visits in your own home at a time to suit you, and, really important - given the lack of postnatal care available these days - ongoing, consistent care and support after the birth for six weeks. If you can't access private health insurance have a look at our website
http://www.neighbourhoodmidwives.org.uk and the different packages on offer because we have a range of prices and always work very closely with the NHS so it's a very comprehensive service whichever one you choose - good luck!