Too much of a good thing?

Laura
I am so nervous because I read that too much vitamin A is extremely dangerous for a fetus- it can cause birth defects and congenital heart defects. I've bee so lucky throughout this pregnant with no morning sickness or food aversions that I am able to eat really well, tons of fruit and veggies, salads, fortified cereals and milk, etc. but I'm also getting 4,000. IU of vit A through my prenatal vitamin. I'm wondering if I should stop the prenatal since my diet is pretty well balanced? Is it possible to overdo it and cause harm to the baby?!