Would an aborted baby have a Baptism of Blood like other martyrs?
That sounds beautiful, but it won’t work. A martyr is a person who suffers persecution, even death, for his beliefs. An unborn baby does not have beliefs, so I would not consider him “other martyr”. It’s like if I go out, get in my car, and die in a wreck, that wouldn’t make me a martyr, would it? I think there is a special dispensation of grace for babies and young children just like in Deuteronomy 1:39 the children of the Israelites are allowed to enter the Promised Land and they did not share in their parents’ punishment.
They are an extension of the Massacre of the Holy Innocents --- we should mourn them on that day, but also see them as entrusted to the Mercy of God.