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Respiratory characteristics during sleep in healthy small-for- gestational age newborns
L Curzi-Dascalova1, P Peirano, E Christova
1INSERM, Hopital Robert Debré, Paris, France.
Insights
Small-for-gestational age (SGA) infants born with intrauterine growth restriction (IUGR) exhibit altered respiratory control at birth. These infants show increased central respiratory pauses and periodic breathing compared to appropriate-for-gestational age (AGA) infants.
Area of Science:
- Neonatal Physiology
- Respiratory Control
- Developmental Pediatrics
Background:
- Small-for-gestational age (SGA) infants, often resulting from intrauterine growth restriction (IUGR), present with neurological and neurophysiologic differences, modified heart rate variability, and increased morbidity.
- Limited data exist on the impact of IUGR on respiratory function in newborns.
Purpose of the Study:
- To investigate the impact of IUGR on respiratory function in newborns at different conceptional ages (CA).
- To compare respiratory patterns between SGA and appropriate-for-gestational age (AGA) infants.
Main Methods:
- Polygraphic recordings were performed on 57 newborns (31 AGA, 26 SGA) aged 35-41 weeks' CA.
- Infants were assessed during active sleep (AS) and quiet sleep (QS) during their postnatal stay.
- Clinically and neurologically normal infants with no abnormal events in the first year were included.
Main Results:
- SGA infants across all CA groups exhibited significantly higher incidences of central respiratory pauses (RP) and periodic breathing (PB), along with a higher apnea index (AI).
- Respiratory frequency was similar between SGA and AGA infants, but the age-related modifications in RP, AI, and PB were disturbed in SGA infants.
- State-related and individual breathing characteristics were similar between SGA and AGA infants.
Conclusions:
- Healthy SGA infants demonstrate significant modifications in the establishment of respiratory rhythm control compared to AGA infants.
- These respiratory dysregulations may stem from subtle brainstem alterations due to decreased blood supply and chronic hypoxia in IUGR.
- Patterns of state-related breathing were preserved, suggesting specific impacts of IUGR on respiratory control maturation.
Objective:
Small-for-gestational age (SGA) infants born with intrauterine growth retardation (IUGR) differ from appropriate-for-gestational age (AGA) infants by: a) alterations in a number of neurologic and neurophysiologic characteristics; b) modified heart rate variability during the neonatal period; and c) increased morbidity rates during the first months of life. However, there are no data on the impact of IUGR on respiratory function at birth.
Methods:
We studied newborns who were 35 to 36, 37 to 38, and 39 to 41 weeks' conceptional age (CA): 31 were AGA and 26 were SGA. All were clinically and neurologically normal at birth and none exhibited abnormal events during the first year of life. Polygraphic recordings were performed between two meals during the normal postnatal stay in the maternity ward.
Results:
During both active sleep (AS) and quiet sleep (QS), SGA infants in all CA groups had significantly higher values for the incidence of 2 to 4.9 seconds and 5 to 9.9 seconds central respiratory pauses (RP), the apnea index (AI) [AI=% of nonbreathing time], and the time spent with periodic breathing (PB), as compared with AGA infants. Respiratory frequency was usually similar in SGA and AGA infants. In addition, the trend of age-related respiratory modifications was disturbed in SGA infants, as compared with AGA infants: at 39 to 41 weeks CA, SGA infants had no significant decreases in RP, AI, or PB, and no increase in respiratory frequency. However, between-state differences were similar in both groups. In all AGA and SGA infant groups respiratory frequency seemed to be an individual characteristic: infants who breathed faster during AS breathed faster during QS, and vice-versa.
Conclusion:
Our data demonstrate significant modifications in the establishment of respiratory rhythm control in SGA infants, whereas the patterns of state-related and subject-dependent breathing characteristics were similar in SGA and AGA infants. We speculate that the dysregulation of respiratory function control maturation observed in healthy SGA infants may be related to subtle brainstem modifications attributable to the decreased blood supply and chronic hypoxia associated with IUGR.