Back in the day I had a friend with a kid. She didnt bring him, but she attended the singles ward...... oh, actually I knew another girl who came, with her baby. She didn't stay active for long though.
Yes, my now sister-in-law. She was in the singles ward when single, then got married, got pregnant on her honeymoon and got divorced 11 months after her marriage. Because her baby was tiny and because the bishop knew her and what she'd been through, she came back to the singles ward. Her baby was too young for even nursery so it was no problem. And my now-husband would go with her to help her with the baby. However, when the child got old enough for Primary, she voluntarily started attending a family ward, since there was obviously no Primary where she was. I think there may been another woman in a similar situation in the ward too for a while.