She is the fire's third victim. Her sons, aged four and seven, died the night of the fire.
When first responders arrived at the scene of the fire, the woman was taken to the hospital in critical condition. Officials said she inhaled quite a bit of smoke.
Her newborn child was also in critical condition; the baby is still alive.
The father of the family was not in the apartment at the time of the fire. He has been treated in hospital for shock.
Quebec’s provincial police said the fire started around 6:30 p.m. on the second floor of a four-unit apartment building on des Écoles Street in Drummondville.
The cause of the fire has not yet been determined.