Two days after giving birth ... Jwoww arrived home from the hospital Tuesday carrying her precious cargo -- but she let her fiance carry the baby.

Jwoww held tight to her breast-feeding pillow ... while fiance Roger Mathews toted their newborn daughter, Meilani, in a baby carrier.

They were greeted by "Jersey Shore" co-star Snooki ... who's preggo with her 2nd bambino.

Nice balloons, Snook.