Blood pressure normative values in preterm infants during postnatal transition

Background The normative blood pressure values in preterm infants still not well defined during postnatal transition. We aimed to create normative blood pressure (BP) reference values in preterm infants <29 weeks gestational age recorded hourly during the postnatal transition. Methods We included only data from hemodynamically stable newborns. Only BP values measured by umbilical arterial catheter (UAC) were included. The regression model showed that only gestational age and postnatal age in hours determine the BP. Results We included 206 out of 547 admitted preterm infants. The BP increases with increasing gestational ages and overtime during the postnatal transition. We constructed 5 BP centile values for each gestational group. BP histograms show that the BP most of the time fluctuated between the 5th and 75th centile values, particularity during day one of life. Conclusions The BP trend values gradually increase in stable preterm infants during the postnatal transition, and preterm infants who do not follow this trend might require hemodynamics assessment. Impact The normative blood pressure is increasing gradually during the first 3 days after birth and is different with gestational ages. This is first normative blood pressure centile values in stable preterm infant and based on invasive blood pressure monitoring. The data enable more accurate monitoring of hemodynamics in preterm infants during postnatal transition.