Hi E.,
After three miscarriages, my OB, an amazing doc and fertility specialist found that I had both MTHFR and a pro-thrombin mutation (another clotting issue). He put me on one baby aspirin a day until I was pregnant (this I will be taking for the rest of my life) and then, the second we found out that I was pregnant, he started me on the daily shots in my stomach of Lovenox (I much preferred this blood thinner to heparin and was lucky that my insurance covered it - they are only once a day and come in pre-filled shots). The last month of pregnancy you have to switch to heparin though as it's half-life is shorter which is needed in case you go into labor early.
They were uncomfortable to give myself in the beginning and caused some bruising, but as time went by, it was nothing, especially since I knew I was helping my baby. My doc just told me to be extra careful when I was hiking, etc. not to fall for fear of bleeding. And, with time all the bruising went away.
I am not sure if this would have been the same treatment for just MTHFR, but, for a pro-thrombin as well, it was something that I would definitely not want to stop suddenly. Make sure your friend gets the right reason for stopping all of a sudden.
My doc is great, he's in BH and takes a lot of insurances. Please let me know if you would like his information if she'd like to see him to get his input.
I know that he had so much to do with me now having a healthy and strong 17-month-old baby girl.
All the best to you and your friend.