"Babies' stress levels double if they are put in a cot straight after being born, a study has revealed.
Separating infants from their mothers at night makes them far less likely to sleep, claim scientists from South Africa.
The research showed the practice of putting newborns in nearby cots to give their mothers some rest after labour can cause distress, revealed the Daily Telegraph.
Babies are also separated from their mothers if they are premature or in need of medical attention, while worries over cot death stop many parents sleeping with their newborn children.
Scientists at the University of Cape Town looked at the effect of early separation by monitoring the heart rates of two-day-old babies when they were alone in a cot or being nursed by their mothers skin to skin.
The results, published in Biological Psychiatry, reportedly showed that stress levels among babies rose 176 per cent when they were alone, and that they were 86 per cent less likely to sleep soundly.
Researchers separated newborn animals from their mothers to monitor stress levels.
They are planning further research to see whether early separation has long-term effects on the health and development of newborns, said the newspaper.
Dr Barak Morgan, the author of the study, said: 'It is standard practice in a hospital setting, particularly among Western cultures, to separate mothers and their newborns...
'Separation is also common for babies under medical distress or premature babies, who may be placed in an incubator.
'In addition, the experts specifically recommend against co-sleeping with an infant, due to its association with Sudden Infant Death Syndrome, or SIDS.
'This research addresses a strange contradiction: in animal research, separation from the mother is a common way of creating stress in order to study its damaging effects on the developing newborn brain.
'At the same time, separation of human newborns is common practice, particularly when specialised medical care is required, such as incubator care.
'Skin-to-skin contact with the mother removes this contradiction, and our results are a first step towards understanding exactly why babies do better when nursed in skin-to-skin contact with mother, compared to incubator care.'
Dr John Krystal, the editor of Biological Psychiatry, said: 'This paper highlights the profound impact of maternal separation on the infant.
'We knew that this was stressful, but the current study suggests that this is a major physiologic stressor for the infant.'"
Newborn babies' stress levels DOUBLE if they're put in cots