For the study, researchers at the Centre for Women's Mental Health at The University of Manchester examined almost 1.5 million births in Denmark between 1973 and 1998, including 7,021 stillbirths.
The risk of stillbirth and newborn deaths from any cause was at least twice as high for mothers admitted with a serious psychiatric illness than for women with no such history.
"We found that the chances of stillborn or newborn death from all causes were greater for babies whose mothers had a serious mental-health illness," lead researcher Dr Kathryn Abel, working with Danish colleagues at Arhus University, said.
"The risk of stillbirth for women with schizophrenia was twice as high than healthy mothers, while women with affective disorders were also more than wice as likely to give birth to stillborn babies," she added.
Women with other psychotic illnesses, including mood-affective disorders, manic depression and drug and alcohol addiction, were also shown to have a much greater risk of stillborn and newborn deaths.
The risk of stillbirth due to complications during delivery among women with drug and alcohol problems was more than double that of healthy women.
Women with affective disorders were more than twice as likely to give birth to babies with congenital abnormalities, leading to stillbirth.
"For most causes of death, offspring of women with schizophrenia had no greater risk of stillbirth or neonatal death than other psychiatrically-ill mothers," said Abel, who is based in the University's School of Medicine.
"The fact that the link between the cause of death and the illness of the mother varies, suggests that factors other than the mental disorder itself are involved.
"Lifestyle, such as smoking and poor diet, and less antenatal care and poverty can also increase the chances of complication during childbirth.
"These findings suggest that further resources are needed to support these vulnerable women and their children," Abel added.