Pregnancy and birth complications are unlikely to play a role in the development of schizophrenia in children, say US researchers.

"Pre-, peri-, and postnatal obstetric complications are reported to be more frequent in adult patients with schizophrenia and have been linked to both greater severity and to 'earlier' age of onset (before either age 18 or 22) in studies of adult patients," explain Dr Anna Ordoñez, from the National Institute of Mental Health in Bethesda, Maryland, and colleagues.

To investigate this possible association, the researchers compared the pregnancy and birth records of 60 children with childhood-onset schizophrenia with those of 48 of their siblings without the disorder.

The findings revealed that the participants' mothers were no more likely to have experienced obstetric complications during the pregnancy and birth of a child who later developed schizophrenia than during the pregnancy and birth of one who did not develop the mental health disorder.

However, the team notes that there was an increase in the prevalence of maternal vomiting during pregnancies in which the child later developed schizophrenia.

The researchers therefore conclude: "Obstetric complications, with the possible exception of maternal vomiting, are unlikely to play a major role in the etiopathogenesis [development] of childhood-onset schizophrenia."

The research is published in the current edition of the journal Biological Psychiatry.