Developmental vulnerability higher in offspring of younger, older mothers
Although children born to young mothers are at the highest risk of developmental vulnerabilities, including physical health and well-being as well as language and cognitive skills, a small increase in risk was observed in children born to mothers aged older than 36 years.
“In recent decades, there has been a shift toward later average age at childbearing in high-income countries, underpinned by an increasing proportion of women giving birth at older ages, combined with a reduction in teenage pregnancies,” Kathleen Falster, PhD, MPH, from the Center for Big Data Research in Health at the University of New South Wales, Sydney, Australia, and the National Center for Epidemiology and Population Health and the Center for Social Research Methods at Australian National University, and colleagues wrote.
“Because a woman’s childbearing age is related to biological, social, economic and behavioral factors that may impact a child’s development from conception through childhood and child development relates to later health and well-being, understanding the relationship between maternal age at childbirth and child development is important,” the researchers added.
To measure the risk of developmental disability in a child at 5 years of age in relation to their mother’s age at birth, Falster and colleagues linked population-level perinatal, hospital and birth registration datasets with data gathered from the Australian Early Development Census. The researchers also used school enrollment information from New South Wales (NSW). Data pertaining to the children from birth to their first year of school, beginning in 2009 or 2012, were examined.
When information was collected, Falster and colleagues analyzed the outcomes of these children, including physical health and well-being, emotional maturity, social competence, language and cognitive skills in addition to communication skills and general knowledge, through child development reports completed by teachers. The researchers defined developmental vulnerability in children if they had domain scores below the 10th percentile cut point in the 2009 Australian Early Development Census.
Of the 99,530 children included in the study, the mean age of their mothers when they gave birth was 29.6 years (SD, 5.7). A small number of children were born to mothers younger than 20 years of age (4.4%), and 20.1% were born to mothers 35 years of age or older.
Nearly one-quarter of children were identified as developmentally vulnerable in one or more domains (21% overall). Children had the highest likelihood of vulnerability when their mothers were 15 years of age or younger (40%; 95% CI, 32-49).
The researchers observed the least amount of vulnerability in children born to mothers aged 30 and mothers no older than 35 years (17%-18%). When children were born to mothers between the ages of 36 and 45 years, the likelihood of the child having one or more vulnerabilities increased to 17% to 24%.
When the researchers adjusted for sociodemographic characteristics, a decreased vulnerability was observed in children born to younger mothers; however, adjusting for some modifiable characteristics, such as prenatal visits, did not significantly impact the outcomes of children at any maternal age.
“Although [children born to young mothers] experience the highest risk, our data illustrate there is a continuing decline in the risk of developmental vulnerability with increasing maternal age, from children born to the very youngest mothers through to mothers in their early 30s, and this is largely underpinned by disadvantage,” Falster and colleagues wrote. “Furthermore, few children are born to young mothers.”
“In this context, policies and programs that target disadvantaged mothers and children rather than focusing on children born to young mothers alone are likely to reach more children at risk of poor development outcomes and have a greater impact on child development at a population level,” the researchers wrote. – by Katherine Bortz
Disclosures: The authors report no relevant financial disclosures.