Failure to thrive in children, most commonly caused by nutritional factors, is defined using growth curves. Children with failure to thrive are identified by a fall across two centile channels or a fall below the second centile for at least three months. Family dynamics, parent-child interaction, and household factors appear to play a precipitating role. It is not known if maternal depression is associated with failure to thrive. O’Brien and colleagues investigated the relationship between postnatal depression and failure to thrive.

In this case-control study, the authors used the Edinburgh Postnatal Depression Scale to evaluate a community-based population. Children younger than two years who met the criteria for failure to thrive were included in the study. The authors visited the families at home, where the mothers completed the depression survey and a Hospital Anxiety and Depression Scale. Matched control patients were identified from the same clinic population. Mothers who scored higher than set threshold values were interviewed to determine whether they had experienced a depressive episode.

The final analysis included 763 children (196 in the index group and 567 in the control group). Significantly more women in the index group scored at or above threshold values on both depression scales compared with the control group. A depressive episode was identified in 21.4 percent of index mothers and 11.1 percent of control mothers. In the low-scoring group, 11.1 percent of index mothers had a depressive episode compared with 4.2 percent of control mothers. In the index group, the rates of depression were similar whether the children’s faltering growth was transient or persistent.

The authors conclude that depression rates are higher in mothers of children with failure to thrive compared with mothers of children in the normal weight range. They suggest that depression affects maternal interaction, which has a negative impact on breastfeeding. This study could not establish a causal relationship between postnatal depression and failure to thrive, but the authors state that their findings warrant screening for postnatal depression. Treatment may improve parent-child interaction, which would benefit the child’s nutrition and growth.