In English we can use the impersonal pronoun "it" for babies:
She gave birth to a baby, but unfortunately it died to illness shortly after
What pronouns are appropriate to use in Chinese? Is 它 fine?
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I would argue that most people would not use "it" for any human in English, since it is dehumanizing. Most people, if the gender is unknown would say "they". However that is separate from your question of equivalent, so lets answer what you want to know:
Using 它 would have the same effect in Chinese as English, dehumanizing etc. so can be the equivalent of English "it" for a person. In both languages this can easily be insulting so use with proper intent and care.
Chinese does not have a gender unknown pronoun "they" like English, but you can default to 他 when gender unknown and that will work well. Alternatively you can simply say "baby" with no pronoun like 寶寶 etc.
Realistically, if you wanted to write less personally, the best choice is to not put anything at all. There is no reason in Chinese to add such a thing when it is already clear you are talking about the baby, doing so is itself emphasis. An example sentence where in English we would put a pronoun but it is completely unneeded in Chinese: 嬰兒吸著奶瓶/The baby drank their bottle.