The effects of genetic liability for schizophrenia and maternal smoking during pregnancy on obstetric complications

Ellman, Lauren M.; Huttunen, Matti; Lönnqvist, Jouko; Cannon, Tyrone D.

doi:10.1016/j.schres.2007.03.004

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Volume 93, Issue 1 , Pages 229-236, July 2007

The effects of genetic liability for schizophrenia and maternal smoking during pregnancy on obstetric complications

Lauren M. Ellman
- UCLA Psychology Department, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095-1563), United States
- Corresponding author. Tel.: +1 310 794 9673 (Work); fax: +1 310 794 9740.
Matti Huttunen
- The Department of Mental Health and Alcohol Research, National Public Health Institute, Mannerheimintie 166, 00300, Helsinki, Finland
Jouko Lönnqvist
- The Department of Mental Health and Alcohol Research, National Public Health Institute, Mannerheimintie 166, 00300, Helsinki, Finland
- Department of Psychiatry, University of Helsinki and Helsinki University Central Hospitale Department of Psychiatry, University of Helsinki and Helsinki University Central Hospital, P.O. Box 22, Valskariankatu 12, 00014, Helsinki, Finland
Tyrone D. Cannon
- UCLA Psychology Department, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095-1563), United States
- University of California-Los Angeles, Department of Psychiatry and Biobehavioral Sciences

Received 6 October 2006; received in revised form 11 March 2007; accepted 14 March 2007. published online 10 May 2007.

Abstract

The purpose of this study was to determine whether a genetic vulnerability for schizophrenia and/or health-risk behaviors among schizophrenic pregnant women were associated with an increased incidence of obstetric complications (OCs).

Method

A high-risk birth cohort was formed by searching the Finnish Perinatal Register for all births from 1991–2000 with arterial cord pH values below 7.20, an indication of fetal asphyxia. This database was merged with national hospital discharge registries to determine psychiatric morbidity of the mothers and the mothers' first-degree relatives. Mothers were divided into 3 groups: women diagnosed with schizophrenia/schizoaffective disorder (n=53), mothers with a first-degree relative with schizophrenia/schizoaffective disorder (n=590) and healthy controls (n=36,895).

Result

Schizophrenic women had significantly more OCs than mothers with a first-degree schizophrenic relative and controls. These women had significantly increased rates of eclampsia, premature delivery, prenatal hospitalizations, and marginally significant increases in high blood pressure. Offspring of schizophrenic mothers had significantly decreased APGAR scores and birth weight and increased medical complications after birth. In contrast, women with a schizophrenic first-degree relative had no significant increases in OCs compared to controls. Schizophrenic mothers also smoked more than the other groups and smoking was found to mediate the relationship between maternal schizophrenic status and decreased birth weight among offspring.

Conclusions

Maternal schizophrenia during pregnancy leads to an increased risk of OCs, possibly due to engagement in health-risk behaviors during pregnancy, such as smoking, whereas genetic susceptibility to schizophrenia, by itself, does not appear to be related to incidence of OCs.

Abbreviations: (OC), Obstetric Complications, (Sz), mothers with schizophrenia/schizoaffective disorder, (Fhx), mothers with a first-degree relative with schizophrenia/schizoaffective disorder

Keywords: Schizophrenia, Pregnancy, Obstetric complications, Gene-environment covariation, Behavioral genetics, Health-risk behaviors