10 wk old baby not smiling

[IcouldstillbeJoseph]

DD is DC2 and 10 wks. Saw HV today about something else and casually mentioned how miserable DD is and hasn't smiled. Perhaps, at a push, I could say we'd had a tentative smirk but even that is exaggerating it.
Anyway, HV wants me to see GP but I'm wondering what exactly he's going to do about it??
She follows objects and looks at lights etc so I'd like to think it's not a eyesight problem...
I know you shouldn't compare but her brother was grinning a lot by 6wks.

Developmental milestones are not set in stone. I suppose the GP might check her responses in other areas but I'm sure they've already been done?

Was she born full term? I wouldn't panic...I would leave it for a couple of weeks or so and then think about checking perhaps?

Yes, born at 39 weeks. I've made an appointment for 2 weeks in the hope we won't need it

What happened at the 8 week check?

We have them at 6 weeks here and my GP just ticked it off in the book without asking - and she definitely didn't smile during the check. The appointment that I have is with the same GP...