Right phonetic
包 supplies the sound — bāo shifted to bǎo by tone change only.
包 itself depicts a fetus wrapped in the womb (the
巳 inside) — by extension 'to wrap, contain'. Faint semantic flavour: a
饱 belly is a wrapped/full container of food. Same phonetic in
抱 (hug),
跑 (run),
炮 (cannon),
泡 (bubble).