Your baby will be getting the visa on arrival but make sure you enter Qatar within 3 months after the delivery. well, even after getting the on arrival visa you have to visit medical commission to spent a 100 riyals there (just a formality, not need to do any tests for your baby they need only the money)and then after getting the confirmation message through metrash head towards any of the emigration service centers with your & your newborn's passport copy. You will get the Visa & ID card for your newborn instantly.

Thanks.