Investing in breastfeeding support may help reduce social inequalities

1 July 2022

Breastfeeding matters for children’s cognitive development, but disadvantaged mothers who give birth at the weekend are less likely to breastfeed, owing to poorer breastfeeding support in hospitals, finds a new UCL study.

The new research, published in the American Economic Journal: Applied Economics, found that children, born in 2000-02, whose mothers left school before age 17 and who were breastfed for at least three months, gained higher scores in cognitive assessments up to age 7 than those from similar backgrounds who weren’t breastfed. The researchers suggest that improving breastfeeding support for disadvantaged mothers may benefit their children’s cognitive development.

Co-author, Professor Emla Fitzsimons (UCL Centre for Longitudinal Studies) said:

“Given the importance of breastfeeding for cognitive development, this research raises the question as to how we can best support disadvantaged mothers who wish to breastfeed but are struggling to do so. The importance of providing hands on infant feeding support in maternity wards should not be under-estimated, and follow-up support in the early days is vital too.”

The researchers analysed data collected from a nationally representative group of almost 6,000 children born across the UK in 2000-02 whose mothers left school before age 17 and who had a natural or low risk delivery. The sample was drawn from the Millennium Cohort Study (MCS), a longitudinal study which has been following the lives of around 19,000 children since they were born. When they were 9 months old, their mothers were asked whether they had breastfed and for how long. At 9 months, 3, 5 and 7, they reported whether their children had any health problems, and from age 3, they also reported on their children’s emotional development. At ages 3, 5 and 7, children undertook a series of cognitive assessments. The research did not observe children’s health while they were still being breastfed.

The study analysed the effects of breastfeeding durations of at least three months, close to the recommended duration at the time of their infancy, compared to those who breastfed for a shorter duration than this or not at all.

Among disadvantaged mothers, those who gave birth at the weekend were around six percentage points less likely to breastfeed for at least 90 days than those who gave birth during the week. For example, 27% of disadvantaged mothers who gave birth on Monday went on to breastfeed their children, compared to only 21% of those who gave birth on Saturday.

Lower educated mothers of children born on a Friday or Saturday were less satisfied with infant feeding advice obtained in hospital compared to mothers of Monday-borns, according to data taken from the Maternity Users Survey 2007. Neither pattern – differences in rates of breastfeeding and hospital feeding support by timing of birth – existed for mothers who had stayed on in education past secondary school.

Children who were breastfed for at least 90 days gained, on average, 8% higher scores in cognitive tests during childhood than those from similar homes who weren’t breastfed, scoring particularly higher in school readiness and speech and vocabulary assessments. The study found no statistically significant benefits from breastfeeding on health or emotional development for this group, up to age 7. However, the research was unable to assess whether breastfeeding had other health benefits, such as increased immunity against disease.

Co-author, Professor Marcos Vera-Hernández (UCL Economics) said:

“This new study shows that children of lower educated mothers who are born at the weekend are less likely to be breastfed compared to those born during the week. They also tend to score worse in cognitive assessments to age 7. As core maternity services for low risk births remain consistent throughout the week, our study shows that it is differences in support for breastfeeding on the weekend that makes the difference.”

The study uses a novel approach to understanding the causal impact of breastfeeding on cognitive development, by using variation in day of the week of birth among natural births to estimate the gains in children’s later development due to breastfeeding. The research provides extensive evidence to rule out other factors that might vary by day of birth, such as maternal and birth-related characteristics, which are shown not to vary by timing of birth, nor do a range of other hospital maternity services. Therefore any differences observed in children’s subsequent development can plausibly be attributed to breastfeeding.

Notes to Editors

For more information or to speak to the researchers involved, please contact:

Ryan Bradshaw, UCL Centre for Longitudinal Studies. T: +44 (0)207 612 6516,  E:

Kath Butler, UCL Centre for Longitudinal Studies. T: +44 (0)20 7911 5389, E:

Fitzsimons, E, Vera-Hernandez, M. ‘Breastfeeding and child development,’ is published in the American Economic Journal: Applied Economics.

Media coverage of this research

The Guardian – Breastfeeding improves cognitive ability for children of poorer mothers – study

BBC Radio 4 Woman’s Hour

Study methodology notes

Breastfeeding and timing of birth

The study’s authors considered various background factors to isolate the effects of breastfeeding on cognitive development, health and emotional development, focusing their analyses on natural, uncomplicated births, and dropping those born to higher educated mothers, those admitted to intensive care, multiple births, those not born in a hospital and those born in Northern Ireland.

Hospital Episode Statistics administrative data on all births in English public hospitals from 2000-01 showed that the babies’ and mothers’ readmissions within 30 days of discharge did not differ by the day of the week, suggesting that the quality of core maternity services, related to labour, delivery and maternal and child health, were not different by day of the week.

Breastfeeding and children’s development

When their children were aged 9 months, mothers were asked to report on any health problems for which their children had been taken to the GP, health centre or health visitor, or to casualty, or for which they had called NHS direct.

Measurements of children’s health and socioemotional development was based solely on mothers’ reports, while the measurement of children’s cognitive development was from children’s responses to objective assessments set by the interviewer.

The Millennium Cohort Study (MCS) is following 19,517 young people born across the UK in 2000-02, building a uniquely detailed portrait of the children of the new century. The last survey of parents and children took place in 2018-19 when the study members were age 17. Data from the Age 17 Survey is now available. The MCS is funded by the Economic and Social Research Council and a consortium of government departments, and managed by the UCL Centre for Longitudinal Studies at the UCL Social Research Institute.

The UCL Centre for Longitudinal Studies (CLS) is a resource centre based at the UCL Social Research Institute. CLS is home to four national longitudinal cohort studies, which follow the lives of tens of thousands of people. The Centre is funded by the Economic and Social Research Council (ESRC).

The UCL Social Research Institute (SRI) is one of the leading centres in the UK for multidisciplinary teaching and research in the social sciences. Based at the UCL Institute of Education, and with more than 180 academic, research and professional staff, it works to advance knowledge and to inform policy in areas including gender, families, education, employment, migration, inequalities, health and child/adult wellbeing.

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