The birth of your first child is something magical, you want to embrace this feeling of accomplishment and bliss for as long as you can. But, there is paperwork to do and each country has its own timelines.
A came across this deadline issue one day, when I was just about to leave the Courthouse and helped a British couple with a quick translation. They wanted to register their baby, to get her on the family file, get a birth certificate and order a passport.
However, more than 30 days had passed since the birth of their new family member, due to caesarean and the mother not being able to leave the hospital, and thus the registration cannot take place the usual, easy way.
They could have registered the child through the hospital, which have 72 hours to do so, and just formalize the documents after leaving the hospital, but they failed to do so.
Now, it is not considered a "normal" registration procedure and they have to present all kind of documents to the civil registration office and may even have to wait 6 months to get their baby's birth certificate! A long wait if you want to travel back to your home country with your baby!
Official Spanish site about registration of new-borns: