both are designed exactly for pre conception and pregnancy. however I would probably take the Sanatagon, as it has higher doses of folic acid.
I am actually on prescription folic acid of 5,000 as I had one pregnancy affected with neural tube defects.
I was taking the 400 mg of it on my first pregnancy, but unforunately in some women this condition affects causing a much higher dosage of prescription folic acid.
It its for this reason I would say the Sanatogen it has higher than the recommended UK amount