Time Course Study of Blood Pressure in Term and Preterm Infants Immediately after Birth

Objective: To describe temporal changes in systolic, diastolic, and mean blood pressure (SBP, DBP, and MBP, respectively) in term and preterm infants immediately after birth. Methods: Prospective observational two-center study. In term infants SBP, DBP, and MBP were assessed non-invasively every minute for the first 15 minutes, and in preterm infants every minute for the first 15 minutes, as well as at 20, 25, 30, 45, and 60 minutes after birth. Regression analyses were performed by gender and respiratory support in all neonates; and by mode of delivery, cord clamping time, and development of ultrasound-detected brain injury in preterm neonates. Results: Term infants (n=54) had a mean (SD) birth weight of 3298 (442) g and gestational age of 38 (1) weeks, and preterm infants (n=94) weighed 1340 (672) g and were 30 (3) weeks gestation. Term infants' SBP, DBP and MBP within the first 15 minutes after birth were independent of gender or respiratory support. Linear mixed regression analysis showed that preterm infants, who were female, born vaginally, had delayed cord clamping and did not require positive pressure ventilation nor develop periventricular injury or ventriculomegaly, had significantly higher SBP, DBP, and MBP at some measurement points within the first hour after birth. Conclusions: We present novel reference ranges of BP immediately after birth in a cohort of term and preterm neonates. They may aid in optimization of cardiovascular support during early transition at all gestations.