Although child mortality has dropped worldwide, approximately 250 million (43%) children in low and middle income countries are at risk of not meeting their developmental potential because of extreme poverty and stunting.
The first 1000 days in a child's life, starting from conception, are recognised as a crucial period of development, yet many children are exposed to poor sanitation, infections, lack of nurturing care and inadequate stimulation during this period. New estimates suggest that children who do not meet their developmental potential may forfeit up to a quarter of average adult earning capacity, and that the overall cost to countries can be as much as two times their national expenditure on health.
The findings come from a new three paper Series on Early Childhood Development, published in The Lancet, which sets out the importance of providing nurturing care - defined as care which promotes health, nutrition, security and safety, and early learning - in helping children achieve their developmental potential. While most families provide this care for their children, many cannot because of poverty, poor working conditions, violence or lack of supportive policies.
The authors find there is good evidence supporting programmes for early childhood development - from Sure Start in the UK, Early Head Start in the USA to Chile's Crece Contigo, or Grade R in South Africa (paper 3, panel 2) - but that many programmes are challenged by inadequate and uncertain funding or lack of resources.
"Increasing numbers of children are surviving, but begin life at a disadvantage because they do not receive the nurturing care they need. Political prioritisation, legislation and financing of early childhood development programmes are key to ensuring their success, as is creating a policy environment that supports nurturing care, for instance by providing paid maternal and paternal leave, free preschool education and support for breastfeeding," says Series author Professor Linda Richter, University of the Witwatersrand, Johannesburg, South Africa. 
"Our economic analysis shows that the cost of inaction is huge, and in many countries far exceeds their spending on health. Supporting nurturing care is a wise investment, and one that should be prioritised in all countries," says Series author Professor Gary Darmstadt, Stanford University School of Medicine, Stanford, USA. 
Children at risk of poor development
New analysis, published in The Lancet Global Health to accompany the Series, provides updated estimates of the number of children at risk of poor development. While there are as yet no universal standards for measuring child development, there is strong evidence that exposure to stunting and extreme poverty are associated with poorer cognitive and educational development, poorer adult health and lower income.
The analysis estimates that in 2010, 249.4 million (43%) children in low and middle income countries were at risk of poor development as a result of stunting and extreme poverty, having decreased from 279.1 million in 2004. In sub-Saharan Africa, 66% of children are estimated to be at risk of poor development due to stunting and poverty, 65% in South Asia, and 18% in the Caribbean and South America (TLGH article, figure 3 for map).
Evidence strongly suggests that parents, caregivers and families need to be supported in providing nurturing care. A number of policies are known to be effective, yet large gaps remain in delivery (paper 3, table 1). For example:
- Free early education: Attending pre-school benefits children's primary school performance, especially when programmes include both education and nutrition, yet only 43% of countries provide at least one free year of pre-school education. Even in high income countries, nearly a third do not provide free pre-school education. Only 40 countries provide the recommended 2 years of free pre-school education (paper 3, fig 2B).
- Paid leave: Parental leave can support bonding and care of young children. Today, all but 8 countries guarantee paid maternity leave, and most provide at least 12 weeks, paying at least two thirds of wages. However, this often does not cover the informal sector and only 77 countries provide any paid leave for fathers.
- Breastfeeding: Breastfeeding reduces the risk of several childhood diseases and improves cognitive function. 139 countries guarantee breastfeeding breaks for at least 6 months, and in 43 countries paid breaks are guaranteed. However, this does not cover the informal sector, and many women are unable to breastfeed in jobs where locations for breast milk pumping or refrigeration are not available.
- Minimum wage: Having a basic income can help provide children with basic needs including healthcare and education. Although minimum wage policies are in place in 88% of countries, many do not guarantee an income that is above the poverty level of $2 per day for a parent supporting a child (paper 3, fig 2A).
Beyond these important ways to support parenting, improved nutrition for mothers and young children, maternal mental health care and prevention of child maltreatment and violence play a crucial role. While health services are particularly well placed to reach children, coordinated action across multiple sectors is needed - with education to improve learning, and with child and social protection to reach the most vulnerable populations.
Affordability & cost of inaction
To assess the affordability of interventions, the authors estimate the cost of scaling up two interventions aimed at promoting nurturing care and treating maternal depression . Scaling up to 98% coverage would cost an estimated additional US$34 billion over the next 15 years for both interventions (paper 2, table 2), amounting to an additional cost of $0.5 per capita in 2030 or a 10% increase in expenditure over previously published estimates for a comprehensive set of women's and children's health services .
The authors also estimate the cost of inaction. For the 249.4 million children in low and middle income countries at risk of poor development due to extreme poverty and stunting, their average adult income per year is likely to be reduced by approximately 26%. At a national level, the cost of inaction in the future can be far greater than some countries' current national health expenditure (paper 3, table 3).
In a linked Comment, Dr Margaret Chan, Director General of the World Health Organization (WHO), Anthony Lake, Executive Director of the United Nations Children's Fund (UNICEF) and Keith Hansen, Vice President for Human Development at the World Bank, write: "The early childhood agenda is truly global, because the need is not limited to low-income countries. Children living in disadvantaged households in middle-income and wealthy countries are also at risk. In targeting our investments, we should give priority to populations in the greatest need, such as families and children in extreme poverty and those who require humanitarian assistance. In addition, we have to build more resilient systems in vulnerable communities to mitigate the disruptive influence of natural disasters, fragility, conflict, and violence."
NOTES TO EDITORS
Funding for the preparation of the Series was provided by the Bill & Melinda Gates Foundation and the Conrad N Hilton Foundation through WHO and the US Fund for UNICEF, respectively.
 Quote direct from authors and cannot be found in the text of the Series.
 Interventions were based on the Care for Child Development programme and the WHO Thinking Healthy package.
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