Older maternal age is associated with better health and development in young children, a large observational study from the UK has found.

A random sample of children from the Millennium Cohort Study (MCS) and the National Evaluation of Sure Start centres (NESS) were studied at nine months, three years and five years of age. In total 31,257 infants aged nine months (18,552 from the MCS and 12,705 from the NESS), 24,781 three year olds (15,590 and 9,191 respectively) and 22,504 five year olds (15,246 and 7,258 respectively), and their mothers, were evaluated.

Geographical weighting was applied to ensure that socioeconomically disadvantaged and ethnic minority populations were adequately represented.

Data on unintentional injuries, hospital admissions, immunisation uptake, BMI and overweight status as well as assessments of language development and social and emotional difficulties measured using validated questionnaires, were collected. These were compared with maternal age at childbirth and adjusted for relevant variables (for example, the child’s gender and birthweight; and maternal class, educational attainment, smoking and parity).

Compared with offspring of 20-year-old mothers, the children of mothers aged 40 years or older scored significantly better in all domains, with the exception of immunisations at age three years.

The authors concluded that the MMR autism scare, which was newsworthy at the time, accounted for this. When MMR results were excluded from the analysis no significant differences in immunisation uptake were seen for children of older compared with younger mothers.

Children of older mothers were significantly less likely to sustain accidental injuries, and be admitted to hospital, and were more likely to have better language skills and fewer social and emotional problems than the children of younger mothers, at nine months, three years and five years of age.

In children aged three years, the risk of unintentional injury fell from 36.6% for those with mothers aged 20 to 28.6% for those with mothers aged 40 and hospital admissions from 27.1% to 21.6% respectively.

Language development scores were 0.21-0.22 SDs lower for children of younger mothers compared with those of older mothers, at five and three years of age. With regard to social and emotional problems, the score for three-year old children of mothers aged 20 was 0.28 SDs higher than for those of mothers aged 40, and 0.16 SDs higher respectively in five year olds.

Child BMI and overweight status were unrelated to maternal age but associated with maternal BMI.

The excellent quality of data collection and the low attrition rates suggest that the conclusions of this study are valid.

Deferred motherhood, often because of career demands, is increasing rapidly in the UK and other developed countries. Although pregnancy can be a daunting prospect for older women, not least because of the increasing risks of chromosomal anomalies and preterm birth, this study will provide some reassurance to women considering pregnancy or fertility treatment in their late thirties and forties.

Dr Chris Barclay

• Sutcliffe AG, Barnes J, Belsky J et al. The health and development of children born to older mothers in the United Kingdom: observational study using longitudinal cohort data. BMJ 2012;345:e5116