Abstract â–¡ 148

Objective. Avoiding prone sleep and the use of a pacifier were reportedly associated with lower risk for sudden infant death syndrome (SIDS). The study aimed to analyse usual sleep position in 2-4-month-old infants, age known for highest incidence of SIDS, and to assess their ability to spontaneously modify sleep position with special regard to use of a pacifier and behavioural characteristics as estimated by the Carey Early Infancy Temperament Questionnaire (EITQ).

Subjects and methods. 192 randomly selected clinically healthy 2-4-month-old infants born in St. Petersburg in 1997-1998 entered the survey. The mothers were asked to complete the questionnaires addressing infant, maternal, and demographic major characteristics as well as sleep routine and other child care practices with particular emphasis on the use of a pacifier, as well as to fill in the EITQ enabling one to score 9 different aspects of infant temperament: activity, rhythmicity, approach, adaptability, intensity, mood, persistence, distractibility and threshold. Since no local wide intervention campaign against pronation has been launched, the parents were likely to follow their and (or) infantile natural inclination when choosing baby's sleep position.

Results. Of 181 infants for whom the mothers were able to define typical position the baby was put to sleep and/or found, 174 (96.1%) were usually put to sleep non-prone: 103 (56.9%) on the back, and 71 (39.2%) on the side. In 51 of 181 cases (28.2%) the babies habitually changed their position when found. Of 174 babies usually put to sleep non-prone, 6 (3.5%) usually turned to front. Putting baby to sleep on the side compared with on the back bore the risk to turn to front equal to 3.01 (95% Cl: 0.42 - 34.0). Initial sleep position and the ability of a baby to change it did not depend on any of the infant, maternal, demographic characteristics and bedding practices. Of 192 infants, 117 (60.9%) were usually left to sleep with a pacifier. There was no significant association between the use of a pacifier and position the baby was usually put to sleep and found. Statistically significant association was found between position modification and infant persistence, known as an ability to maintain specific activity, and the lowest persistence was a feature of the babies usually put to sleep supine and found prone, while the highest one of the babies both put to sleep and found supine. Infants who used pacifiers appeared to have more rhythmic behaviour compared with non-users, and this effect remained after adjustment has been made for major potential confounding and/or modifying factors, including gender, parity, details from perinatal history and familial social background, feeding pattern, bed- and room sharing. Except rhythmicity, no significant association was found between the use of a pacifier and any other particular feature of infant temperament.

In clinically healthy 2-4-month-old babies, use of a pacifier associated with more rhythmic behaviour does not have major influence on the choice of sleep position and infant's propensity to spontaneously modify it during sleep. Increased risk of a baby put to sleep supine to be found prone is associated with low persistence.