Cara- Calcium does have a constipating affect so that is why it might bother some people with C. I am surprised that your prenatal only has 200mg. I think the one I am on right now has at least 600mg in it. You might benefit from it because it will help slow your D down. I just started my prenatal called Prenate GT. I was so worried about the iron in it because it contains 90mg. Last time I was so C with it, but acutally this time around I am going just fine. In fact the problems i was having earlier in the month are gone. Go figure?