I've already heard this question a few times (being pregnant or not), and I'm sure I'll hear it a few more times in the coming months. In case any of you are interested this is my answer to the question, "Is Breast Milk Vegan?"
I do not think of animals as food. Since I was very little I've felt strongly that animals were my buddies and didn't see them as a food source. I became vegetarian after watching Charolette's Web and realizing what the meat industry was. My earliest memory of this connection to animals, is when I was 2 years old and screaming at the top of my lungs for the stray Cat I named, "Nona" (after my mom's tap dance teacher) to "COME TO MEEEEEEEE!" My 2 year old self didn't understand that rationalizing with (or screaming at) Nona would gain her affections. At that point I was still learning English, and wasn't well versed in communicating with cats and animals like am I now. Don't worry I'm not digressing here.
Not seeing animals as food, but as living, breathing, sentient beings who feel pain, feel emotions, love their babies and families, is not how most people initially or intuitively see animals. A lot of people may deep down understand that connection, but many times choose to ignore it because they "love bacon," or just want to feel they are more important as a species. If you love bacon, go raise your own pigs, kill them yourself, and butcher the meat yourself, and eat it. If you still, "love bacon" at that point, I will at least have some more respect for your choice (though the thought of that to me is completely revolting and I would never EVER kill another living being on purpose- in particular for my own gain - which I think a lot of meat eaters when faced with it feel the same way), but most people don't want to see the suffering. They choose to ignore that, and just see the animals as a means to an end- as food. They, "know" about the slaughter houses, but they don't want to see the blood. They'd rather see the McNuggets or whatever. Most people. Remember I'm generalizing here.
As a vegan, am I against dairy milk completely? Am I against mother cows giving cow milk to their babies? Of course not. Its not that dairy should never be seen as a source of nutrition, or as a food source, its that I don't believe its a natural food source for people - especially for people who take advantage of their power over another living being, and exploit that power for selfish personal gain. Seeing the animal as a commodity, I feel is morally wrong, and I don't think its a good way to live life. Mothers should only give milk to their babies.
So breast milk? Is it vegan for me to feed my baby as nature intended, and as I see fit for my own child to be nurtured with what I'm naturally endowed with for the sole (heh soul) purpose of feeding him/her? Am I exploiting myself to nourish my baby? Am I not consenting? Do I feel like there is an unequal balance in the power dynamic where one part is not seeing the other as a living/breathing/sentient being capable of feeling pain, emotions and love? Absolutely not. Which is why I don't see breastfeeding as having anything to do with being or not being vegan, because being vegan isn't "just a diet"- Its not, "oh no milk! run away!" Its a deep set of moral and philosophical perspectives on living without harming others (physically, emotionally, spiritually...) to the best of our abilities.
Covering my baby in fur and leather is not vegan as much as someone breaking into my house and stealing my breast milk without my consent and selling it for their own gain without any respect or acknowledgement of me as a living being with emotion and who experiences pain. That's when breast milk is not vegan. Haha. Yuck, right? Get it?