The researchers from the Centre for Women's Mental Health at Manchester University say 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.
The researchers studied almost 1.5 million births in Denmark between 1973 and 1998, including 7,021 stillbirths and 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, along with Danish colleagues at Arhus University, says the risk of stillbirth for women with schizophrenia and women with affective disorders, was twice as high as for healthy mothers and 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.
Dr Abel says the risk of stillbirth due to complications during delivery among women with drug and alcohol problems was more than double that of healthy women and women with affective disorders were more than twice as likely to give birth to babies with congenital abnormalities, leading to stillbirth.
Dr Abel says for most causes of death, offspring of women with schizophrenia had no greater risk of stillbirth or neonatal death than other psychiatrically-ill mothers but 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.
Dr Abel says lifestyle factors such as smoking and poor diet, less antenatal care and poverty can also increase the chances of complication during childbirth.
For this study ??“ the first to examine the impact of incubator care on adult depression ??“ the research team studied a subsample of 1212 children recruited from a longitudinal study launched in 1986. Children were recruited from Quebec kindergartens and facts on birth condition, obstetrical complications and incubator care were obtained through hospital medical records. Participants received psychiatric assessments when they were 15 and 21 years old. Researchers found that:
Of the 16.5 percent babies placed in incubators only 5 percent suffered major depression by age 21. Among participants who were not placed in incubators, 9 percent developed depression, which is the average rate for general society. Correlation between decreased depression and incubator care remained after factoring participant age, weight at birth, family adversity or maternal depression.
The research team also found that girls were three times less likely to experience depression by the age of 15 if they had received incubator care at birth. "This difference was due to the fact that more girls experience depression than boys during adolescence and how boys suffer depression in later adolescent years," says co author Frank Vitaro, a Universit?© de Montr?©al professor and member of the Research Unit on Children's Psychosocial Maladjustment.
Chain of biological and emotional factors
The research team found that direct and indirect stimuli ??“ not just incubators per se ??“ could decrease depression. For instance, incubators are controlled environments where body temperature, brain oxygenation, sound and light are adjusted to maximize neuronal development. What's more, children who received incubator care as babies typically received more emotional support from their mothers throughout childhood because they were perceived as more vulnerable.
"Incubator care was not the sole factor that shielded participants from future depression," says first author David Gourion, formerly of the Universit?© de Montr?©al and Sainte Justine Hospital Research Center and now at psychiatrist at the H??pital Sainte-Anne in Paris.
"We believe that incubator care is a trigger for a complex chain of biological and emotional factors that helped decrease depression."