Non-nutritive sucking in sick preterm infants

Background: Non-nutritive sucking (NNS) by the newborn infant is a fundamental behaviour and is one of the first coordinated muscular activities in the fetus. Aims: Our objective is to study the NNS pattern in prematurely born infants, who had various conditions commonly associated with immaturity. Method: A specially designed computer-based method that analyses and quantifies components of the NNS pattern was used. Subjects: The pattern of 51 clinically stable prematurely born infants (gestational ages 26-35 weeks) making a total of 206 observations were analysed and findings were compared with those obtained from 58, healthy preterm infants. Results: The rhythmic NNS pattern of alternating sucking and pauses was elicited in all examined infants, the earliest at post-menstrual age (PMA) 26 weeks. The role of PMA, the dominant predictor for several sucking variables seen in the control group, became diminished for the infants with risk factors but changes were otherwise similar. The infants' sucking activity and sucking frequency increased and the variability of the pattern declined with increased PMA and weight. Follow-up of a subgroup of infants revealed fewer sucking bursts per minute, slower sucking frequency and a greater variability of the frequency and amplitudes in those infants who developed sequelae. Conclusions: It would, thus, appear that the NNS pre-programmed rhythm generator, primarily modulated by maturation in healthy preterm infants, becomes affected by known risk associated events and in infants who later develop sequelae. Quantification of the NNS pattern in preterm infants may be a valuable future component of their evaluation. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.