You still need two documents though, original attested birth certificate and valid passport of the baby. You have to take care of your residence permit also. The parents, both father and mother, should have a valid residence permit in Qatar and the wife should be on the sponsorship of husband.
Credit: Qatar day
URL:http://www.qatarday.com/blog/information/returning-to-qatar-with-your-new-born-baby-know-the-visa-rules/28132