A well-planned vegan diet is safe and beneficial for all stages of life, including pregnancy. That being said, making sure that one is eating a balanced diet (just like a pregnant omnivore would) and paying attention to the intake of vitamin B12 (which is usually found in animal products) are advised. Iron (leafy greens and lots more), vitamin D (mushrooms), calcium (leafy greens and lots more), and iodine (kelp/seaweed/prunes/lima beans) are easier to come by than B12, but should also be payed attention to. All of these can be easily supplemented if necessary.
I understand that people want to be careful when it comes to their pregnancy and the health of their kid. There's no need to add in any animal products to get the nutrients that a person's body needs, even the increased/slightly different needs during pregnancy.
Break it for the child's sake? What do you mean by that? As long as you keep it safe for the child, there is no issue and therefore no reason to not be vegan during pregnancy
For me, the questions is rather "what supplements do you consider a 'must take' during pregnancy" :)
Why. The child would only then not get everything it needs when the mother doesn't get everything she needs. That's a concern that people should have for every diet.
Now when you think that you might not get every nutrient, then just make some research and look into what's important. You can find so much information about it. It's not a reason to pay for animals to suffer and die when there is no necessity right?
Generally speaking the folks here are right, you should be able to maintain veganism unless things go really sideways. I'd recommend getting in touch with a dietician though if you're really worried (not a nutritionist, different beast) and having them go over your plans. Iron deficiency is a particular risk, one that can be easily surmounted as long as you're aware of it... Way harder to keep iron up when pregnant even than usual, and it's already tough as we all know.