Why does my baby move his head side to side when sleeping?

The only thing that I can think of is that the baby can be dreaming of what I don't know. I hope that helps you some if you need to know more that that then you can take the baby to his Doctor and run some test and see if there can be something Else wrong good luck on finding out.

Hi, engaged position is basically that the head in down into the top of the cervix ie ready for birth. There is nothing really keeping bub there( apart from the fact there isn't much room left) so they can and do move their heads about a bit. Won't be long now....... Congratulations!

My son did that for a while too. He is now 7 months and I feel like he hasn't done it in awhile. I think its when they are trying to get comfortable. I think it is somewhat common cause I have seen the same question on here a few times.

My 2 kids have done that. My doctor said that they arent comfortable the way they are sleeping and they try to find the right spot. Its nothing to worry about its actually normal.

You know.. my baby does the same thing too..lol. She looks so adorable when she does it too. I think they are feeling hot at the back of their head and those movement help them in airing it. I have no idea why they actually do it but i think thats whats happening...

ask the doc. maybe he's having little baby nightmares.