Obstetric complications in women with schizophrenia

It is not known whether schizophrenic women have increased incidence of complications during pregnancy and delivery. Data from the Danish Medical Birth Register were used to compare 2212 births to 1537 schizophrenic women in Denmark with a random sample of all deliveries in Denmark during 1973–1993 (122931 births to 72742 women). The schizophrenic women had fewer antenatal care visits.

They were at lower risk of pre-eclampsia, but tended to have lower Apgar scores. There were no other differences in the incidence of specific complications such as placenta previa, placental abruption, and abnormal fetal presentation. Schizophrenic women were at increased risk of interventions such as Cesarean section, vaginal assisted delivery, amniotomy, and pharmacological stimulation of labor.

There were no important differences between the deliveries to schizophrenic women who gave birth before and after their first admission to a psychiatric department. These results show no evidence that schizophrenic women have a greater frequency of specific obstetric complications than non-schizophrenic women. Nevertheless, they are at increased risk for interventions during delivery.

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Maternal obstetric complications are widely regarded as environmental contributors to schizophrenia risk, although the evidence is still inconclusive. While meta-analyses of a number of case-control studies suggest that significant associations exist between adult schizophrenia and exposure to obstetric complications, several population-based investigations have failed to demonstrate excess occurrence of obstetric complications in individuals who developed schizophrenia compared to those who did not. The sources of discrepant findings are likely to include different definitions of obstetric complications, the use of retrospective maternal recall versus prospectively collected obstetric data, differences between rating scales, and variation in sample size and selection. A more fundamental problem may be the confounding of observed associations between maternal obstetric complications and schizophrenia by heterogeneity in the degree of maternal genetic risk within samples ascertained through an individual with schizophrenia. Since genetic susceptibility to schizophrenia may be associated with a heightened sensitivity of the developing brain to obstetric insults, varying degrees of transmitted parental genetic risk might result in variable thresholds for the effects of obstetric complications, dependent on their timing, severity, and points of impact. It is, therefore, important to reduce heterogeneity with regard to variables such as genetic risk, severity, and type of obstetric complications.

In this respect, a research focus on obstetric complications in mothers with schizophrenia and their offspring, termed "strategic populations" by Rosenthal, offers a vantage point by being more homogeneous for genetic risk transmitted to the offspring. Children of women with schizophrenia have an eight- to 10-fold higher risk of developing the disorder compared to the general population, and individuals who develop schizophrenia are more likely to have a mother, rather than a father, with schizophrenia. Examination of the following could help clarify whether obstetric complications are a covariant effect of the genetic predisposition to schizophrenia or a concomitant of severe mental illness: