A 19-year-old man who was living with the woman in the northern city discovered the case on Thursday and reported it to police.
Authorities rushed the newborn baby to the hospital, and she fortunately survived and is in stable condition.
Hannover prosecutors' spokeswoman Kathrin Soefker said investigators are now trying to determine who the father of the babies is or are, and an autopsy is being done to determine the cause of death of the second infant found in the suitcase.
The woman, whose name wasn't released in line with German privacy laws, has been arrested on suspicion of manslaughter and attempted manslaughter.
Source: Linda Ikeji Blog