Young children experience heightened stress levels when they enter child care, suggests research.
Heading off for nursery can be a stressful experience
Researchers tracked the reaction of 70 toddlers in Berlin to their separation from their parents and homes.
They found stress levels were still raised months after beginning child care - even though outward signs of distress had stopped.
"For most toddlers the initiation of daycare is a major stress," writes report co-author Michael Lamb.
The study of children's reaction to leaving home casts light on a question that will have been asked by many working parents: "Do children really worry about being away from their parents?"
'Fussing and crying'
The answer from this study suggests that children do experience increased stress - with measurements being based on levels of the stress hormone cortisol in their saliva.
Researchers tracked the 70 children in Berlin, aged 15 months, from before they started childcare, through their first day and then as they adapted and became more accustomed to their childcare setting.
The research found that stress levels increased when children entered childcare and, though lower, were still above normal several months later.
"It is stressful for both infants and children to start spending extended periods of time in noisy new environments separated from their trusted sources of comfort and support," writes Professor Lamb from Cambridge University's faculty of social and political sciences.
Even though levels of "fussing and crying" subside after the first few days, and children stop showing "overt" signs of distress, Professor Lamb says children still have "heightened levels of vigilance or arousal even after they appear to have adjusted to daycare".
These children might also make more compensatory demands for interaction with their parents.
The research suggests there are ways that the impact might be softened - including reducing the length of time in which children are with carers each day, more individualised attention from childminders, and childcare settings which are smaller and more home-like.
But there is also a reminder that stress exists in children even when they seem to have adapted to childcare - and that if children are going to be properly settled and reassured there is a need for parents to provide "child-focused emotional exchange", particularly in the hours before sleep.