Learned behavior

[KYPunk]

She stood in front of the pram
repeatedly smacking I also found this word choice a little confusing. Perhaps 'smothering an unseen cry?' Otherwise, I'd look at changing 'into'. I didn't recognize it referred to the pram until my second pass.
into an unseen cry.
Greasy hair and dirty clothes
her body moved in a way
that hinted at issues No problem with this word. How else would you describe the problems of a stranger? Reading it put a pretty clear picture in my mind.
and sheltered housing. Funny how you can pick up things like that just from someone's hunched-up shoulders.

No eye contact or opinion,
he was somewhere else The change in subject lost me until the end of the stanza. Maybe you could include 'him' and 'her' together before he leaves to go inside for context. This is his first and only appearance.
shrinking into the shopping center,
watching the automatic doors
in crisis. Love it. Brings home the vibe of mistrust and suffering. Picturing him looking wide-eyed back at closing doors.

I caught her hand
holding on at the wrist,
she came back from behind her eyes, This is the moment of contact, no longer relating as an observer, and feels as strong as it should-
a sail boat emerging from a storm. -but this line feels disconnected from the imagery of the rest of the poem. Maybe you could connect it to the previous stanza? (as 'he' becomes distant watching closing doors, she is drawn to focus through open eyes. I think there's a symmetry there to be drawn on.) However, I appreciate this imagery's emotional power. So, if it can't be improved, don't change it! :P

Its nappy was full The alternative to this pronoun issue is a worse one, since the two (parents?) are referred to only by 'he' and 'she', so using one again would be confusing. 'It' is a pretty normal designation for an infant.
clothes covered in sick,
how could I explain what a child needs
to a mother that needed the same? very nice.

This couple, especially the mother, come off as very guarded and fearful people. They avoid eye contact, withdraw, and try to be unassuming, only standing out more. I'm curious to know more about her reaction at being grabbed at the wrist, that bit seems a little abrupt. I would expect some reaction.
The title is perfect as it is. It connects to the closing line, and creates a continuity. It suggests the likelyhood that their parents were similar people, and their child could also be. But then, how could you explain... Depressing but true.
Loved it! Very relatable, poignant, and concludes well. Just a few clarity issues.
Thanks for the read :)