Hi Bethers,
I have Spina Bifida (thankfully quite mildly) so I take a high dose of folate, 5mg. I've heard here that taking folate before you get pg is supposed to actually help you to not be so sick when you are pg. I don't have anything personally to compare it to, so I don't know about that.
I have heard quite a few personal stories about the folate making women sicker when they are pg. For example, my SIL (who has to take the really high dose like me because her husband, my brother, and I are from the same genetic tree) had no NV at all in her family history but was quite sick (normal morning sickness) throughout the first trimester when she took the folate.
However, there is no official research to support this theory. Recent discussions with my various doctors have brought me to the thought that it would have been difficult for the folate to have made things so severe for me, as I was digesting so little while the HG was at it's worst. Weighing up the risk of a child of mine living with even my limitted set of complications (and they can be SO much worse than what I have) against 9 months of turning myself inside out on a daily basis, my baby's needs win every time. Folate doses have so significantly reduced the incidence of my disability that I would never not take the folate.
If you want to know more about it, one Spina Bifida information website is
www.sbv.org.au . This is my local Spina Bifida foundation's website.
The main point is that the folate is most important in the earliest stage of pregnancy. If you and your partner have no genetic connection to Spina Bifida, 1mg or even .5mg should be enough for you to take to rule out the random incidence of the condition. Any that you digest is better than none.
good luck with your planning
Amanda