Pregnancy with a MVR

I am a 31yr old female who has a mechanical mitral valve. I am taking warfarin daily and will be on anticoagulants for life. I was born with a hole in my heart which was patched when I was 4yrs old but then a hole developed on my MV which was repaired when I was 21yrs old. I then developed endocarditus when I was 27yrs and old and in 2004 had MVR surgery in the UK.

I am fairly fit and regularly exercise although I am a little overweight for my height (according to the charts). I dont smoke and only drink alcohol occassionally.

My husband and I are hoping to have children soon and have just started looking into the options for someone with my condition. I have received various opinions on the best course of action, the main recommendation being to stay on warfarin until I am pregnant and within 6 weeks of this date transfer onto heparin for the full term of pregnancy. The doctors have said there is a risk to both baby and myself but cannot give any percentages etc.

I have been told that I would not be able to have an epidural due to the possible blood loss but they would recommend a natural birth rather than a c-section. I would be monitored on a monthly basis and would have heparin checks every month also (like my INR).

Basically, I wondered if there is any other ladies who have had MVR and are also on warfarin that have gone through a pregnancy - both successfully and unsuccessfully? I would like to know if you changed to heparin and how you were affected and if you now have any side effects.

Thanks so much for any advice offered, its much appreciated.