I'm a nutrition student and I've been quite peeved by the Elevit ad's, they said they are the only "Proven" formulation to avoid certain conditions but you can take folic acid on its own.

I was cranky because you don't need to spend a fortune on one of those "pregnancy" formulations, you can take a good quality standard multi vitamin, just check the vitamin A amount isn't too high, and add extra folic acid if you need to, it's a lot cheaper.