The premature birth was caused by a detachment of the placenta, according to Hola.
This is the first child for the 42-year-old first cousin of King Felipe VI.
Maria was staying with friends in Pozuelo de Alarcón, a suburb of Madrid, when she went into labor on Saturday. Although the baby is now in an incubator, he and mom are doing fine.
Her family, including King Juan Carlos, has been very supportive. It is understood that Juan Carlos will be named as one of the yet-unnamed baby's godparents.
Doña Maria has a degree in translations and interpreting from the European University. She is fluent in English, French Portuguese, Italian and German, and of course, her native Spanish. In 2002, she founded her own business Zesauro Traducciones.