Maternal mental health problems were assessed in pregnancy, and at three, six and 12 months post partum using the Edinburgh Postnatal Depression Scale (EPDS). The EPDS is a ten-item self report scale designed to identify women experiencing depressive symptoms in the postnatal period ( Cox et al., 1987 ), and has also been validated for use in pregnancy ( Murray and Cox, 1990 ). The point prevalence of depressive symptoms at each time point was based on EPDS scores ≥13, the standard cut-off score recommended when screening for probable major depression ( Cox et al., 1987 ; Murray and Carothers1990 ). To include mild depressive symptoms, the original authors recommended a cut-off score of ≥10 ( Cox et al., 1987 ).