Vitamin A aids in both cell development and brain growth, but this vitamin does have a drawback. There have been links between excessive amounts of vitamin A and an increased risk of birth defects, especially neural tube defects. (Be careful not to eat too many protein, breakfast, or meal-replacement bars, each of which may have 100% of your daily value of vitamin A. Get into the habit of checking the Food and Drug Administration (FDA) nutrition labels on everything you eat.)
Aim for this amount: Consume no more than 15,000 international units (IU) a day while pregnant or just before becoming pregnant.