Our ped missed it until DSs 6 months appt (just one thing in a long line of issues with her). Since he was older than 6 months we had to get special permission to get a scan. He is complete fine.

I have the 1% story. No other abnormalities- physical or developmental.

My best friend's baby has one which was missed at his newborn and 3m check ups. The bed noticed it at his 6m check up, told them it was extremely likely nothing to worry about, they went for imaging and he was diagnosed with a tethered spinal cord. The earliest surgery he could get was at 9.5 months, but unfortunately he was already cruising around furniture at that age. They had to keep him horizontal for two weeks (at home) after the surgery and it was ridiculously hard bc of the age. And the hospital gave them virtually no tips. They were trying to strap him to the changing table, mom was constantly dangle nursing over him, they were offering him the iPad above his head, zooming snacks from above down into his mouth... for 14 days. It was insane. Just sharing this because your baby is so young, if there was an issue needing addressing, you would not have go through this part thankfully!

He is 15 months now and walking normally which is a great sign. The next two big things will be seeing what happens during potty training- if he has control of his bladder. And then seeing if he has sexual function during puberty. He will have multiple surgeries over the years. It was a HUGE shock at first, but they have come to accept it and found a great team of doctors to make a plan.

Same story for us. My son has one, totally normal.

From what I was told, there is generally other abnormalities noted at birth if there is a spinal cord fusion issue

Both of mine had them and were sent for imaging and both are fine. They're 6 and 3 now and I haven't thought about it since!

My 3yo was also sent for imaging at like 7mo bc his head grew "too fast" or something that could have signified too much fluid. That was scary but also ended up being nothing.