CNRS: Scientists observed the effect of preterm babies'
clothing on their behavior. Newborns placed in a sleep sack were less active
and touched parts of their bodies less frequently than those dressed in a
simple bodysuit. The scientists suppose that the former may have been more
stressed for two reasons: their movements were hampered, so that comforting
self-touching was less frequent. This study is published on 17 March 2015 in Scientific
Reports.
It
is well known, particularly from animal studies, that early experiences of life
can have long-lasting effects on the emotional and social development of
individuals. Scientists at the Laboratoire Éthologie Animale et Humaine were
thus able to show that the wrapping and manipulation of foals in certain stud
farms just after birth had long-term behavioral effects1. However, in human
infants, the possible immediate or longer-term consequences of routine
practices2 remain a matter of debate.
This is particularly true for preterm babies, whose behavioral expression may
be less visible.
In
a new study carried out in collaboration with the Neonatal Medicine Department
at Brest University Hospital, the research team looked at the effect of clothing
on the behavior of preterm newborns. Premature infants (born before 38 weeks of
pregnancy) move from a closed incubator to an open cot under a radiant warmer.
When they are able to regulate their temperature, the warmer is switched off
and they are clothed in pyjamas and a cardigan and placed in a sleep sack
(attached over the shoulders) instead of a simple bodysuit. Video recordings
enabled the scientists to study the behavior, over several hours (spread over
two to four days), of 18 preterm infants aged 34 to 37 weeks post-conception.
Nine of them, still under the radiant warmer, were dressed in a bodysuit
(allowing them freedom of movement), while the other half were wearing the
pyjamas, cardigan and sleep sack.
The
newborns in bodysuits proved to be more active than those in the sleep sack;
their arms were more frequently bent and their hands more often in contact with
their environment or head (the only accessible part of the body). The newborns
in sleep sacks tended to have their arms extended and hands closed, and did not
touch anything. Raising their arms in all these items of clothing appeared to
require too much physical effort for these babies weighing less than 2 kg.
Yet
infants are known to reduce their stress levels through self-touching. In
hospitalized preterm newborns, deprived of any frequent tactile contact with a
parent, it could even constitute a crucial mode of compensation. Furthermore,
having their movements hampered increases the levels of stress in individuals,
giving them a feeling of impotence. By preventing this contact and imposing a
physical constraint, the pyjama-cardigan-sleep sack combination could therefore
have a dual impact not only in terms of immediate discomfort but also perhaps
of emotional and motor development. To verify this hypothesis, the research
team is now planning to explore the behavioral effect of sleep sacks on a
larger group of preterm babies in the longer-term. The present study
nevertheless underlines the importance of paying more attention to routine
practices, even if they appear harmless, during the perinatal period.