The Development of Circadian Rhythms in Human Infants

2.3 Collection of urine samples
Paired urine samples were collected (night and day) on consecutive days for each
week of monitoring. In some cases 48 hours of samples were collected for each week.
Three methods of collection were available to parents: use of Hollister U bag, clean
catch or urine pad.
U bag
The U bag required a clean surface free from creams and ointments to try to
encourage close adhesion of the sticky backing to the perineum. This method was a
victim of its own success, as some families reported a reluctance to detach the bags
once they had collected a sample as they felt removing the adhesive may cause
discomfort to the baby.
Clean catch urine
A second option of urine collection from the babies was given to mothers. This
involved clean catch urine samples – this is used in clinical practice on children‟s
wards around the country. This does require patience on behalf of the mother as it can
be particularly time consuming. This did not prove as popular an option (as was the
case for the U bag) with the mothers, so permission was sought from the ethics
committee to add an additional method of urine collection to the study protocol.
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