Lo is 3.5 month, 4 if you count 2 weeks overdue. He was starting to coo when i talked to him at before 2 month, but then it gradually stopped. He doed an occasional screeching sound at me, and a very occasional "ahoo", but nothing like before. Same with laughter, he was starting to squeal and we even heard a real laugh couple of times, but none of it for a while. He smiles at me sometimes, but other times i can't even get him to look at me. Smiling didn't decline i think. He never mimicked us in any way, except if you count smile. I keep reading that those are red flags for autism and i'm worried sick! He does like being carried, and likes when we make him stand and other physical activities. He's pretty good in this developmental aspect - holds his weight easily and even tries to sit. Today i watched him banging at a toy on his chair and he would occasionally check up on us, which is somewhat reassuring. Im going to talk to the doctor at our next check up, but im afraid of what i might hear... Did any of your kids had similar issues? How did they turn out?
3.5 months is still really tiny, babies go through phases of doing things and then doing them less I think. My DC spent about a week sticking his tongue out and then didn't do it again as he focussed on something else. Talk to your HV, but I would say it's way too early to worry. I would be careful about rushing him to bear weight though - they do that when they are ready. It's not good for their joints to be made to stand early on. He may be ready for some short periods in a bouncer if you want to use one sparingly, but even those are / should be designed so the baby doesn't bear its own weight