My neighbor also has MTHFR as well as a history of pulmonary embolism. She declined the lovenox, but took the aspirin and folic acid, and went on to deliver a healthy boy at 39w6d. Yes, healthy pregnancies do in fact happen, despite all of the horror stories people may tell you.
I didn't know I was homozygous MTHFR C677T until 14 weeks, and I started my shots then. For me, my personal medical history was the deciding factor. I'll do anything not to get that sick again. Even if it only happens to be placebo effect, I'll take it!