I find this paragraph is logical, whether eating your own placenta vegan:
“At first thought eating placenta might be an affront to veganism considering the fact that placenta is an animal bi-product. But I think we decided that eating your own placenta did not foster a cruel exploitation of yourself and is, therefore, vegan.” http://lciz.blogspot.sg/2011/10/is-eating-your-own-placenta-vegan.html