Go to safefetus.com and look up berrocca it gives a good overview of it it states:

"The doses of Vit. B1, B2, B6, B12, C, nicotinamide and pantothenic acid are above the recommended dietary allowance in pregnancy.

No adequate human data, reported possible association between high doses of Vit C and anencephaly and infantile scurvy, of Vit. B1 and anencephaly, of vit B6 and phocomelia and infantile convulsions.

No data for biotin in pregnancy.

The dose of calcium is within the RDA in pregnancy, unknown RDA for magnesium, both minerals should be avoided in the first trimester because of possible teratogenicity, but safe in the second and third trimesters if chronic high doses are avoided.

Chronic ingestion of magnesium may cause neonatal hypermagnesemia, drowsiness, respiratory distress, CVS impairment and decreased muscle tone."

The other week when I was very sick and couldn't eat much i had half a tablet, my doc said half a tablet no more than 3 times a week is fine as its just the magnesium that's the problem in first trimester (which is where I am)

Hope that helps