Does unwantedness of pregnancy predict schizophrenia in the offspring? Findings from a prospective birth cohort study

Background. We sought to replicate (or refute) a previous report of an association between unwantedness of a pregnancy and the risk of schizophrenia in the offspring. Method. The study was conducted using a large, prospectively collected birth cohort as part of the Prenatal Determinants of Schizophrenia study (PDS). Attitude toward the pregnancy was assessed at the time of the mother's first visit to the prenatal clinic. Cases of schizophrenia and other schizophrenia spectrum disorders in the offspring of these mothers were subsequently ascertained and diagnosed. In univariate and multivariate analyses, we examined the relationship between attitude toward the pregnancy and risk of adult schizophrenia and other schizophrenia spectrum disorders. Result. The unadjusted hazard ratio for the association between ambivalent or negative maternal attitude toward the pregnancy and the risk of schizophrenia spectrum disorders was 1.75, (95% CI = 0.97, 3.17, P = 0.06). This result was unchanged after adjustment for social class, paternal age, race/ethnicity and other potential confounders. Similar results were observed when only cases with schizophrenia were included in the analysis. Conclusion. We did not find a statistically significant association in favor of the hypothesis that unwantedness of pregnancy is a risk factor for adult schizophrenia. On the other hand, the magnitude of the observed association was similar to the findings of the only previous study of this question and the confidence limits overlap those findings. Whether unwantedness of pregnancy is a risk factor for adult schizophrenia remains an open question that may be resolved by future research.