Development of baroreflex control of heart rate in preterm and full term infants.

AIM To study baroreflex maturation by measuring, longitudinally, baroreflex sensitivity in preterm (gestational age 24-37 weeks) and full term infants. METHODS Baroreflex sensitivity was quantified once a week, one to seven times, by a totally non-invasive method. RESULTS Baroreflex sensitivity at birth was lower in the preterm infant and increased with gestational age. It also increased with postnatal age, but the values for the preterm infants at term still tended to be lower than the values for full term babies. CONCLUSION Baroreflex control of heart rate is present in the premature infant, but is underdeveloped and increases with postnatal age. Ex utero maturation seems to be delayed compared with in utero maturation assessed by full term values. These results may reflect sympathovagal imbalance in preterm infants and could identify a population more vulnerable to stress.