"The baby boy, weighing 2.35 kilos (five pounds three ounces), was born after 32 weeks without complications and by Cesarean section," announced the Lisbon hospital that carried out the procedure.
The mother had been declared brain-dead on February 20 after suffering a brain haemorrhage, the hospital said.
"The foetus appeared to be in good health," it added, so "the decision was taken with the family to follow through with the pregnancy."
The hospital said the successful birth represented Portugal's longest-ever survival of a foetus whose mother was brain-dead.