Baking companies are voluntarily adding folic acid to some of their breads, in the hope the Government will not make it mandatory.
The B vitamin folate in folic acid has been shown to help prevent neural tube defects, which causes spina bifida in babies.
In August, the Government introduced a moratorium on the mandatory introduction of folate, when it became unclear just what its benefits or side-effects are.
The Medical Association says mandatory fortification would ensure that pregnant women, unaware of their body's need for increased folate, could still obtain sufficient amounts.
But the Baking Industry Association says consumer choice is important and that more research needs to be done to establish if folate is a risk to the general public.
Buyers advised to check ingredient list
The companies don't want it to be made compulsory because then, they say, consumers will have no choice.
The chief executive of Couplands Bakery, Annette Campbell, says any customer not wanting to eat folic acid should check the ingredient list, because it is already in some breads.
Jenny Reid of the Food Safety Authority's science group believes the bakers are being responsible about sticking to agreed levels of folate.