This has happened a couple of times to me now. Resetsim doesn't work. It's really hard to interact with an invisible baby. I managed to age the baby up on the first one but then she went all weird looking. Adult body with long limbs & her face in her crutch area.
This 2nd time the mother was carrying the baby from the hospital but the baby is missing from her arms. There is no picture on the side of the screen, there is a square but no picture in it. And there is a line across the screen. I quit the game & restarted it but the same thing happened but no line across the screen.
So I quit the game again went into edit town & switched to another household before she went into labour. Played the other house for a while & then went back to the invisible baby household to see what happened in my absence. And she's had the baby but its missing. No picture on side, she's got a picture of a pink dummy showing she's had a girl. But no baby. This has happened a lot in my town, when I jump toa different house the baby disappears & nothing brings them back. I've tried resetsim I've tried (with the help of someone from this forum) a MOD that helps find missing sims but that doesn't work either.
Now I'm stumped!