The Development of Circadian Rhythms in Human Infants

There is general agreement, that although the exact timing of maturation of
physiological systems in infants cannot be pinpointed, most system maturation has
occurred by 6 months of age, and definitely by 12 months. Previous work by our
research group has pointed toward months two to four as being crucial, in terms of
physiological maturation and so it was decided to concentrate on this period.
The notion of „passiveness‟ associated with the first few postnatal months, with a
baby just „feeding and growing‟ with a doubling in birth weight (Chamley et al 2005)
is being dispelled. It is in fact a time when the speed of change in developmental
parameters (Tanner, 1989) may create a period of increased vulnerability and there is
a move towards strengthened diurnal rhythms and systems (Bee & Boyd, 2007). This
study will focus on the rapid and unique changes which occur during infancy only.
The fact that physiological changes occur at within a narrow and critical time period
confers increased vulnerability and susceptibility to the infant. This may be borne out
by the fact that the peak of mortality in the post natal period still occurs at 3 to 4
months of age with Sudden Infant Death Syndrome being the main and the leading
cause of death in the western world, despite successful public health campaigns and
improved healthcare (Mitchell et al., 2007). The question has been raised - are there
any other health interventions that could be introduced that would allow for SIDS
rates to fall even further? And if so what is the science behind them that may explain
why it in fact occurs?
How does an infant navigate this potentially „stormy‟ period of life and successfully
make it to the other side? What determines how and when physiological changes
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