Should Newborn babies Sleep Alone?


Up to now, it has been common practice to expect newborn babies to sleep alone in the western world, however, there has been no specific research on the physiological impact on the young babies.

One simple way of measuring the stress response is through heart rate variability (HRV), which is influenced by level of arousal, which can be accurately quantified during sleep. Sleep is also essential for optimal early brain development.


To investigate the impact of maternal separation in humans, we measured HRV in 16 2-day-old full-term newborns sleeping in skin-to-skin contact with their mothers and sleeping alone, for 1 hour in each place, before discharge from hospital. Infant behavior was observed continuously and manually recorded according to a validated scale. Cardiac interbeat intervals and continuous electrocardiogram were recorded using two independent devices. Heart rate variability (taken only from sleep states to control for level of arousal) was analyzed in the frequency domain using a wavelet method.


Results show a 176% increase in autonomic activity and an 86% decrease in quiet sleep duration during MNS compared with skin-to-skin contact.


Maternal-neonate separation is associated with a dramatic increase in HRV power, possibly indicative of central anxious autonomic arousal. Maternal-neonate separation also had a profoundly negative impact on quiet sleep duration. Maternal separation may be a stressor the human neonate is not well-evolved to cope with and may not be benign.

Evidence from a quiet MRI

Breastfeeding benefits babies’ brains

A study using brain images from “quiet” MRI machines adds to the growing body of evidence that breastfeeding improves brain development in infants. Breastfeeding alone produced better brain development than a combination of breastfeeding and formula, which produced better development than formula alone.


Support for the developing brain MRI images, taken while children were asleep, showed that infants who were exclusively breastfed for at least three months had enhanced development in key parts of the brain compared to children who were fed formula or a combination of formula and breastmilk. Images show development of myelization by age, left to right. Credit: Baby Imaging Lab/Brown University


PROVIDENCE, R.I.[Brown University] — A new study by researchers from Brown University finds more evidence that breastfeeding is good for babies’ brains.

The study made use of specialized, baby-friendly magnetic resonance imaging (MRI) to look at the brain growth in a sample of children under the age of 4. The research found that by age 2, babies who had been breastfed exclusively for at least three months had enhanced development in key parts of the brain compared to children who were fed formula exclusively or who were fed a combination of formula and breastmilk. The extra growth was most pronounced in parts of the brain associated with language, emotional function, and cognition, the research showed.


The findings are in press in the journal NeuroImage and available now online.

The study showed that the exclusively breastfed group had the fastest growth in myelinated white matter of the three groups, with the increase in white matter volume becoming substantial by age 2. The group fed both breastmilk and formula had more growth than the exclusively formula-fed group, but less than the breastmilk-only group.

“We’re finding the difference [in white matter growth] is on the order of 20 to 30 percent, comparing the breastfed and the non-breastfed kids,” said Deoni. “I think it’s astounding that you could have that much difference so early.”

Deoni and his team then backed up their imaging data with a set of basic cognitive tests on the older children. Those tests found increased language performance, visual reception, and motor control performance in the breastfed group.

The study also looked at the effects of the duration of breastfeeding. The researchers compared babies who were breastfed for more than a year with those breastfed less than a year, and found significantly enhanced brain growth in the babies who were breastfed longer — especially in areas of the brain dealing with motor function.

Deoni says the findings add to a substantial body of research that finds positive associations between breastfeeding and children’s brain health.

“I think I would argue that combined with all the other evidence, it seems like breastfeeding is absolutely beneficial,” he said.

Other authors on the study were Douglas Dean, Irene Piryatinsky, Jonathan O’Muircheartaigh, Lindsay Walker, Nicole Waskiewicz, Katie Lehman, Michelle Han and Holly Dirks, who all work with Deoni in the Baby Imaging Lab. The work was funded by the National Institutes of Mental Health.

Orchids or Dandelions?

Discoveries in genetics in the 90’s and early noughties led to a common view held by scientists that a specific gene variation recently identified was a “vulnerability “ gene as it was often associated with high risk of behavioural trouble, affecting mood and behaviour…. But there were two other very interesting findings:

  1. The association between the gene variant and conduct disorders only occurred if it was combined with a difficult childhood
  2. The combination of that same gene variant and a positive childhood experience created greater strength and happiness

So? this was not a gene variant associated with vulnerability but rather a gene variant associated with responsiveness to the environment: negative environment leading to emotional and behavioural difficulties, positive environment leading to enhanced life. Those children…who grow up into adults of course are the orchids  ….

The orchid children wilt under poor care and thrive when they are well cared for.

The dandelion children, who do not have the gene variant are less responsive to the environment, therefore they do not seem to be so badly affected by poor care nor do they flourish particularly with good care.

If we think beyond the individual to the group level and in society, in order to function well, we need individuals who are likely to be more innovative and unusual (orchids) along with steady resilient individuals (dandelions).

The gene variations which lead to difficulties such as anxiety, ADHD, depression may also lead to innovation and creativity?