The health of the baby mostly comes down to the health of the mother (yes breast milk is vegan), and I'd wager vegan dieters on average to be more knowledgeable about nutrients than your average person. Being deficient in nutrients at such a young age, especially in the womb, can cause permanent damage. So knowing where the gaps are in what you eat and properly supplementing is important, which doesn't just apply to vegans.

On a vegan diet nutrient toxicities from things like iron and vitamin A are less of a concern as well because of the form they are consumed in, as well as toxicity from minerals that shouldn't be there that become concentrated in herbivores and even more so in predators. Also there is a protective effect to certain foods like soy at a young age, where the reverse is true of say dairy.

The essential oils thing in the meme is concerning though. First of all I would associate that with someone who consumes a vegan diet for mystical reasons, probably one containing mostly or all raw food. On such a diet it can be hard to consume enough food for one individual, and now you have to eat enough for baby as well. The other thing I'd be concerned about is toxicity with the oils, especially if they are poorly tested and contain things that aren't supposed to be present in a significant amount.