MONDAY, Dec. 12 (HealthDay News) -- Preterm birth alters the normal maturational increase in baroreflex sensitivity (BRS), which results in significantly reduced BRS during quiet sleep (QS), at a corrected age (CA) of 5 to 6 months, according to a study published online Dec. 12 in Pediatrics.
Nicole B. Witcombe, Ph.D., from Monash University in Melbourne, Australia, and colleagues investigated the effects of preterm birth, postnatal age, and sleep state on control of blood pressure (BP), based on BRS measurements across the first six months of term-CA. A total of 25 preterm and 31 term infants were assessed at 2 to 4 weeks, 2 to 3 months, and 5 to 6 months CA. Using a photoplethysmographic cuff placed around the infant's wrist, BP was recorded during QS and active sleep (AS). Using cross-spectral analysis, BRS (milliseconds/mm Hg) was assessed in one to two minute epochs.
The investigators found that, in preterm infants, there was no significant effect of postnatal age on BRS within QS or AS, whereas in term infants there was a maturational increase in QS. During QS, the BRS of preterm infants was 38 percent higher at 2 to 4 weeks CA and 29 percent lower at 5 to 6 months CA, compared with term infants. Comparing sleep states, in QS at 2 to 3 months CA, the BRS of preterm infants was significantly reduced, by 26 percent, compared with AS.
"Preterm birth has a marked effect on BRS during sleep across the first 6 months CA, possibly reflecting an absence of the normal age-related changes in parasympathetic control of heart rate," the authors write. "Lower BRS during QS compared with AS at 2 to 3 months CA may place preterm infants at an increased risk for cardiovascular instability at this age of peak incidence of SIDS."
Abstract
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