The rationale starts with the pretty solid fact that fluoride makes a profound difference in the shape of teeth formed during
middle pregnancy. The leap is that this same process could be operating during early pregnancy when other organs are formed
in about the same way as the teeth. It is at least possible that fluoride deficiency could contribute to some birth defects.
There is not a reason in the world not to take fluoride in early pregnancy (beyond the general ideas that this is
a time to be very careful and that you are better off listening to your doctor than somebody like me). Fluoride is clearly
a very essential nutrient for healthy teeth just a month or so later, so taking at least a little bit now is not too speculative.
I would suggest a child's dose (.5 mg F per day) during early pregnancy.
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