The Development of Circadian Rhythms in Human Infants

demographics; infant birth weight and gestation, medical history and delivery type)
and advised as to suitable possible participant families.
Subjects were recruited during four monitoring periods; the first from April 2007 to
June 2007; the second August 2007 to October 2007; the third period from January
2008 to March 2008 and the final period from April to June 2008.
The group of subjects were chosen randomly from the ward lists to try to represent the
social class distribution of the geographical area where the study took place. The
Leicester Royal Infirmary has over 6000 deliveries annually and is the largest
maternity unit in Leicester. The spread of social groups among deliveries on the unit
is thought to be representative of that in the local population.
2.1.1 Expression of interest contact on postnatal ward
Mothers were approached for an expression of interest to take part in the study from
the postnatal wards within the first week after delivery. The ward based delivery
record was consulted together with midwifery staff to ensure that the infant fulfilled
the inclusion criteria.
Mothers were approached at bedside and a brief overview of the study given. They
were given a flier inviting them to take part in the study and a patient information
leaflet and a letter with further information about the study (appendix 1). Mothers
who were expressed an interest completed a reply slip containing contact details:
name, address and telephone number.
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