Summary: A new study reports children born to teenage mothers are at increased risk of being diagnosed with developmental problems by age 5 than their peers born to older mothers. Researchers also report children born to mothers over 35 may also have a slightly elevated risk of developmental issues.
Source: University of New South Wales.
Children born to teenage mothers have the highest risk of developmental vulnerabilities at age 5, largely due to social and economic disadvantage, a UNSW Sydney-led study of almost 100,000 school children has found.
The risk declines steadily with every additional year of a mother’s age up to 30 years, then increases slightly after 35 years and older – to a level similar to the risk for children born to mothers in their early twenties.
The study, published in the journal PLOS Medicine, is the largest ever carried out on early child development across the full range of maternal age.
The study analysed data from the Australian Early Developmental Census for 99,530 five-year-old children in their first year of school in the state of New South Wales in 2009 or 2012, as well as their health and demographic data collected at birth.
For the Census, teachers answer questions about a child’s development across five areas: physical health and well-being; emotional maturity; social competence; language and cognitive skills; and communication skills and general knowledge.
Developmental vulnerability is defined as scoring in the lowest 10%, based on 2009 standards. Overall, 21% of the children in the study were identified as developmentally vulnerable in at least one of the five areas.
“We found that the lowest risk of developmental vulnerability – 17% – was among kids born to mums aged about 30 to 35. The highest risk – 40% – was for children of mothers 15 years or younger, and this was mostly underpinned by social and economic disadvantage,” says study first author, Dr Kathleen Falster of the UNSW Centre for Big Data Research in Health, and the Australian National University.
The recent trend around the world for women in high-income countries to delay childbearing was reflected in the age range of the mothers in the study. Only 4.4% of children in the study were born to mothers aged less than 20 years, while one in five children were born to mothers aged 35 years and older.
“The increased risks for the babies of older mothers, such as premature birth and low birth weight, are well known, but until now, there has been limited large-scale evidence on about the developmental outcomes of their children beyond infancy,” says Dr Falster.
“The good news from our study is that the vast majority of kids born to mums aged 35 and older fare well. The elevated risk of developmental vulnerability we identified is relatively small.
“The risk of 17% to 25% for the children born to mothers aged 36 to 45 years is similar to that of children born to mothers in their twenties,” she says.
The early years of life are critical to an individual’s long-term health and well-being, and the study highlights the opportunities available to promote better developmental outcomes in early life.
“While children born to teenage mothers may have the highest risk of developmental vulnerability, few children are born to teenage mothers,” says Dr Falster.
“Our research suggests that policies and programs that support disadvantaged mothers of all ages, including young mothers, may reduce developmental vulnerabilities, supporting more kids to reach their potential.”
The team includes researchers from UNSW, the Australian National University, the University of Adelaide, the Baker Heart and Diabetes Institute, and the University of Manitoba in Canada.
Source: Deborah Smith – University of New South Wales
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Original Research: Open access research for “Maternal age and offspring developmental vulnerability at age five: A population-based cohort study of Australian children” by Kathleen Falster, Mark Hanly, Emily Banks, John Lynch, Georgina Chambers, Marni Brownell, Sandra Eades, Louisa Jorm in PLOS Medicine. Published April 24 2018.
Maternal age and offspring developmental vulnerability at age five: A population-based cohort study of Australian children
In recent decades, there has been a shift to later childbearing in high-income countries. There is limited large-scale evidence of the relationship between maternal age and child outcomes beyond the perinatal period. The objective of this study is to quantify a child’s risk of developmental vulnerability at age five, according to their mother’s age at childbirth.
Methods and findings
Linkage of population-level perinatal, hospital, and birth registration datasets to data from the Australian Early Development Census (AEDC) and school enrolments in Australia’s most populous state, New South Wales (NSW), enabled us to follow a cohort of 99,530 children from birth to their first year of school in 2009 or 2012. The study outcome was teacher-reported child development on five domains measured by the AEDC, including physical health and well-being, emotional maturity, social competence, language and cognitive skills, and communication skills and general knowledge. Developmental vulnerability was defined as domain scores below the 2009 AEDC 10th percentile cut point.
The mean maternal age at childbirth was 29.6 years (standard deviation [SD], 5.7), with 4,382 children (4.4%) born to mothers aged <20 years and 20,026 children (20.1%) born to mothers aged ≥35 years. The proportion vulnerable on ≥1 domains was 21% overall and followed a reverse J-shaped distribution according to maternal age: it was highest in children born to mothers aged ≤15 years, at 40% (95% CI, 32–49), and was lowest in children born to mothers aged between 30 years and ≤35 years, at 17%–18%. For maternal ages 36 years to ≥45 years, the proportion vulnerable on ≥1 domains increased to 17%–24%. Adjustment for sociodemographic characteristics significantly attenuated vulnerability risk in children born to younger mothers, while adjustment for potentially modifiable factors, such as antenatal visits, had little additional impact across all ages. Although the multi-agency linkage yielded a broad range of sociodemographic, perinatal, health, and developmental variables at the child’s birth and school entry, the study was necessarily limited to variables available in the source data, which were mostly recorded for administrative purposes.
Increasing maternal age was associated with a lesser risk of developmental vulnerability for children born to mothers aged 15 years to about 30 years. In contrast, increasing maternal age beyond 35 years was generally associated with increasing vulnerability, broadly equivalent to the risk for children born to mothers in their early twenties, which is highly relevant in the international context of later childbearing. That socioeconomic disadvantage explained approximately half of the increased risk of developmental vulnerability associated with younger motherhood suggests there may be scope to improve population-level child development through policies and programs that support disadvantaged mothers and children.