Seventeen percent of women are not ready when they leave the hospital after having a baby, researchers say.

The study of 4,000 mothers was published in the journal Pediatrics.

Researcher Dr. Henry Bernstein of Dartmouth University said that the factors most related to unreadiness included being a first-time mother, being black, a history of chronic disease, inadequate prenatal care, off-hour delivery.

Berstein said that mothers and care givers must work together to make sure a woman and her baby are ready to go home.

For the study, questionnaires were given to mothers, peditricians and obstetricians on the day a woman was discharged after a full-term pregnancy and delivery. The family was declared unready if any of the three felt the mother should have stayed in the hospital longer.

Federal law requires insurance companies to cover at least a 48-hour hospital stay following childbirth. It goes up to a 96-hour stay in the case of a Cesarean section.