Background:
Offspring of mothers with severe mental illness (case offspring) have higher risk of perinatal and infant mortality compared to those born to unaffected mothers (comparison offspring). The mechanisms underlying these increased risks are unclear.
Aims: Our aims were to assess whether: i) the distribution of mortality outcomes varied between case and comparison offspring; ii)case offspring were more likely than comparison offspring to be exposed to severe obstetric complications; and iii) mortality is associated with maternal severe mental illness after adjustment for obstetric complications.
Methods:
We identified a whole-population cohort of 15,486 case and 452,229 comparison children born in Western Australia 1980-2001. Record linkage across State psychiatric, inpatient, mortality, birth and midwives registers provided mortality outcomes and measures of exposure to obstetric complications and other relevant covariates.
Results:
A higher rate of mortality was observed amongst case children (2.4%) than comparison children (1.5%) (unadjusted OR= 1.6, 95%CI=1.4-1.8). Case children also experienced higher rates of severe obstetric complications and were more often exposed to other sub-optimal early life environments. After adjustment for exposure to obstetric complications, the effect of maternal severe mental illness on mortality was substantially reduced (OR=1.3, 95%CI=1.2-1.5). Further reductions were observed after adjustment for other adverse exposures (OR=1.1, 95%CI=1.0-1.3).
Conclusion:
We observed substantial reductions in the influence of maternal severe mental illness on perinatal and infant mortality rates after accounting for exposure to obstetric complications and other environmental exposures. This highlights the importance of good antenatal care, and continuing social support for all vulnerable child-bearing women.