Heparin vs lovenox?

Lane
After 2 miscarriages (one at 7 weeks in September and one at 9 weeks in January), my obgyn referred me to a fertility clinic.  I now know that I have PAI1 and MTHFR.  I've been put on foguard and baby aspirin.  My doctor also wants to put me on either heparin or lovenox injections once I become pregnant again.  I can't find a lot of information on what the differences, success rates, and/or side effects would be for either.  I've got a follow up visit on 3/8 but I would love any information you ladies might be able to share!