m sure he/she will develop fine, it has more to do with.... will the baby get all of his/her
nutritional needs from your diet. And..not to be flippant, but that depends on how GOOD of a vegan you are.
Do you supplement for the proteins and vitamins that you miss eating meat and animal products in other ways? If you eat a well-supplemented, healthy diet, and have no major deficiencies, chances are your baby will be just fine nutritionally.