Interpreting DOB from Baptism Record: "de xxxxxx dias de nacido"

Is there a more likely interpretation of the date of birth when a baptism record describes an infant's as as "de xxxxx dias de nacido"? xxxxx is a number, siete, quatro, un, etc. I'd like to calculate DOB, but might be wrong by a day if my assumption is wrong. So, generally, was a child "de un dia de nacido" born today or yesterday?

Gracias,

Eduardo
San Jose, CA