if your wife and baby entering Qatar within 90 days you will get the entry visa on arrival at the Airport itself (provided both your wife and you are having a valid RP & Visa - not expired). You must carry the original Birthcertificate along with the passport that they may verify some times. And then, you can apply for RP for the newborn baby as usual. For babies no blood test at the medical commission required, but need to remit the fee there. Only Blood grouping identification required. Hope this is enough for you...good luck.