The grandchildren of adolescent mothers have lower school readiness scores than their peers, according to a study published February 6, 2019 in the open-access journal PLOS ONE by Elizabeth Wall-Wieler of Stanford University, USA, and colleagues at the University of Manitoba.

Previous studies have established that children born to adolescent mothers are less ready for school and have poorer educational outcomes than children born to older mothers. Several mechanisms have been suggested to explain this association, including maternal education levels, social support and monetary resources.

To determine whether this effect extends to multiple generations, the authors used data from the Manitoba Population Research Data Repository to identify 11,326 children born in Manitoba, Canada, in 2000 through 2006 whose mothers were born in 1979 through 1997. Children born in these years took the Early Development Instrument (EDI), a 103 item questionnaire administered by kindergarten teachers to assess five areas of development. The researchers were able to link information from the data repository, EDI scores, and Canadian Census data. Results were adjusted to account for differences in birth year and location, income quintile, and child's health at birth.

A greater percentage (36%) of children whose grandmothers had been adolescent mothers were not ready for school than children whose grandmothers were 20 or older at the birth of their first child (31%). The relationship persisted even when a child's own mother was not an adolescent mother. Compared with children whose mothers and grandmothers were both at least 20 at the birth of their first child, those with grandmothers who were adolescent mothers but older mothers had 39% greater odds of not being ready for school (95%CI: 1.22-1.60). These children lagged behind in physical well-being, social competence, language and cognitive development.

The educational attainment and marital status of mothers and grandmothers was not available in the data, nor was individual income. The mechanisms underlying this multigenerational effect are unclear but the results have policy implications for school readiness interventions as well as calculating the costs and consequences of adolescent motherhood. Interventions to improve outcomes of children born to adolescent mothers should also extend to grandchildren of adolescent mothers, the authors say.

The authors add: "Adolescent childbearing has significant implications for early childhood development -- not just for the child of that mother, but also for the grandchild of that mother."