Hi Heather -
I was also just diagnosed heterozygous MTHFR after two losses (no successful pregnancies yet). My dr did a great job explaining it to me, and I work in health care and took a lot of genetics in college xxx number of years ago, so here's what I know....
We all carry two copies of every gene in our bodies - one from your mother and one from your father. In a heterozygous mutation, one of those two MTHFR genes is mutated. (Hetero = different, homo = same.) Your labs show you have two separate heterozygous mutations, one of MTHFR c677t and one of MTHFR a1298c. But having two heterozygous mutations isn't the same as having one homozygous mutation.
According to my rmc specialist, MTHFR mutations are only known to cause a problem in pregnancy when it's a homozygous mutation, when BOTH copies of an MTHFR gene are mutated (like Amos). This causes an elevated level of homocysteine (an amino acid) in your body, and it's the homocysteine that actually causes all the trouble. The fact that your homocysteine level is normal is good news, and it's exactly what would be expected for having a heterozygous mutation. Amos' labs are exactly what would be expected for a homozygous mutation.
According to what I've read, close to 40% of the general population is MTHFR heterozygous. I've also read that because that percentage is so high, a lot of drs don't actually check your MTHFR, and only check homocysteine levels instead - almost half of the women tested are going to be heterozygous and it freaks us out when it doesn't really necessarily mean anything in regards to our pregnancies.
Now, that said, my dr has elected to go ahead and treat me for it anyway, since the "fix" is simple and can't hurt me or a future baby, and it helps me feel like we're at least doing *something* different next time (other than just crossing my fingers and hoping for the best). He has me taking one baby aspirin/day and up to 4 mg of folic acid/day total. My pre-natal has 1 mg, so I take OTC folic acid to make up the difference. He also has me starting prometrium on 3dpo every month until I get a BFN (or hopefully a BFP, in which case I keep taking it!) He also mentioned Lovenox was a possibility, but I don't feel ready to go there yet...
If you have questions, perhaps go ahead and see the specialist in St Louis, or at least call and see if he/she or the office staff can answer some of them over the phone. I always find that information is the best antidote to worry - the less I know, the more horrible scenarios my brain imagines!
Hope that helps.