Offices in Flensburg on the Germany border with Denmark say the woman - whose name has not been released - feared that her husband would leave her if she had any more children.
PA report that she has been arrested on five counts of manslaughter, and say she has made a 'comprehensive confession' to the killings after handing herself into the police after a six-year investigation was 'closing in' on her.
Ulrike Stahlmann-Liebelt, the head prosecutor in Flensburg, said the woman has two living children, aged eight and 10.
It is thought she began hiding her subsequent pregnancies from 2006, avoiding contact with doctors and hospitals before killing the babies at birth. It is believed she delivered two of the babies at home, and three in nearby woods.
Ms Stahlmann-Liebelt told the Press Association that the woman 'had the impression her husband would leave her if she had any more children, and that's why she didn't tell anyone she was pregnant, including her husband.'
"She has said that the family lived at a certain level of prosperity, that it was clear her husband did not want any more children, and that one reason was to preserve this standard, and she feared that might be endangered if another child were there," she added.
The woman's husband has told police that he did not know about any of the pregnancies, but prosecutors are unclear as to how she managed to conceal them.
Police officers found the first body in a paper sorting station in 2006 about 15 kilometres (nine miles) away from the woman's home town of Husum. The second baby's corpse was found in a parking area off a regional main road.
After reading news reports that DNA results revealed the two children had the same parents, the woman hid her next three babies in boxes in the basement of the building where she lived, rather than dumping them in public places.
Those bodies have now been recovered and post mortems carried out, but a cause of death has not yet been determined.
Police took hundreds of DNA samples from women in the Husum area in a bid to track the mother down. The woman gave herself in after she was forced to provide a DNA sample herself. She confessed to the killings before her DNA sample had been processed.