Background: Maternal stress during pregnancy has been suggested as a risk factor for schizophrenia. We tested the hypothesis that being the child of an unwanted pregnancy would be associated with later schizophrenia.
Methods: Data were collected prospectively in the Northern Finland 1966 Birth Cohort of 11 017 individuals. In the sixth or seventh month of pregnancy mothers were asked whether the pregnancy was wanted, mistimed but wanted or unwanted. Schizophrenia diagnoses in the cohort members were obtained from the Finnish Hospital Discharge Register.
Results: Seventy-six cases of DSM-III-R schizophrenia were identified in the whole cohort between the ages of 16 and 28 years; a cumulative incidence of 0.7%, compared with 1.5% for those born from unwanted pregnancies. The risk of later schizophrenia among unwanted children was raised compared with wanted or mistimed children, even after adjustment for confounding by sociodemographic, pregnancy and perinatal variables (OR 2.4; 95% CI 1.2-4.8).
Conclusions: The results suggest that unwantedness may operate either directly as a psychosocial stress during development making children more liable to schizophrenia, or it may be a marker for behaviours associated with risk in either the mother or the child.