 [ Symptoms ] is a vegan diet safe during pregnancy [ Disease ] the warnings are a bit more urgent for pregnant and lactating women who are vegan having a vitamin b12 deficiency particularly has been shown to impair neurological development in infants nursed by vegetarian mothers a lack of vitamin d and calcium also can result in bone demineralization in breastfeeding women similarly young children under 5 reared on vegetarian and vegan diets can suffer impaired growth that is because of a vitamin b12 deficiency which can also result in anemia and rickets yet a well planned diet can meet all the nutritional needs absorbable calcium is critical too for vegans and ovo vegetarians to protect against weak bones that can lead to osteoporosis