Does heterozygous for mthfr gene mutation affect pregnancy?, and what about taking synthetic folic acid supplement?

Controversial...: Some studies have shown an association between the MTHFR gene mutation and recurrent miscarriages but this is controversial. Aside from this possibility, it doesn't cause problems with pregnancy. If you have this mutation, its a good idea to take folic acid, vitamin B-12 and Vitamen B-6. Aspirin is also sometimes recommended for women for who have had recurrent miscarriages. Best wishes!