Pregnancy questions

My husband and I have 6 living children, ages 9 and under. Suddenly, in the past 5 months, I have had two pregnancy losses, at 20 weeks and 14 weeks, which prompted us for testing.

I tested positive for Homozygote MTHFR 1298, as they called it.
We eat an extremely healthy diet, organic, natural, etc., and treat issues and preventative with herbs and natural as possible, so when I asked my doctor about treatment for the next pregnancy, he said of course Levonox, since he has dealt with this alot. He then called back 5 minutes later to tell me after looking at the rest of the results, he recommends just 4mg of folic acid, the extra b vitamins, and to continue with the high fish oil, etc. for blood thinners and it should be enough.

Is that accurate? We do NOT want to do anyting chemical wise, and anything that could naturally work would be our ideal treatment. What can I possible do without putting anything fake into my system, but increase the chance of a healthy baby next time? Why did it start affecting things now, and not with my other babies?