This is the support for the position.
[Apologies in advance for the wall of text]
In the story of David and Bathsheba, they first conceive a son, who is born sickly, and dies when it is 7 days old. During these 7 days of his son's life, David wears sackcloth and ashes and pleads for his son's life. However, upon hearing of the child's death, David stops mourning and washes himself. When asked about this strange turn of events by his servants, David replies, While the child was still alive, I fasted and wept, for I said, ‘Who knows whether the Lord will be gracious to me, that the child may live?’ But now he is dead. Why should I fast? Can I bring him back again? I shall go to him, but he will not return to me." The full text for the summary from above can be found in 2nd Samuel 12.
Now, the number of days is important because the sons of Israel were to be circumcised on the 8th day, and this child died before he had a chance to be. This means he died outside of the promises, yet David clearly asserts that he will see the child again, which means that either David is going to hell with the child (unlikely) or that the child has been taken to heaven.
Now, there is no Bible passage that clearly asserts where aborted babies or miscarried babies go upon death. So, we take what we know of God and say this is our best answer, but admit that it isn't clearly stated. And I admit that this is a hard question to grapple with for Christians, but I think it's worth grappling with.
Octavia, I know that we aren't philosophically aligned, but I do appreciate your willingness to have an open and constructive dialogue, and I hope that continues. I hope that I have not come off as condescending, as I'm really just trying to honestly elaborate on a difficult subject.