Blood pressure of newborn with gestational age between 26-42 weeks in a tertiary center in Iran

Background and aim: Blood pressure (BP) is a reflection of hemodynamic variables. It is an important vital sign and indicator of clinical stability. Accurate measurement and interpretation of this physiological signal is essential for the optimal management of the ill newborn. An increase in the awareness of hypertension among neonates has resulted to increased ability to diagnose neonates with the disease. Objectives: This study aimed to determine BP values and percentiles in stable newborns in the first weeks of life and evaluate the relevant factors.Methods: This prospective observational study was conducted on 320 term and preterm newborns with gestational age (GA) between 26 and 42 weeks between2015-2017. Exclusion criteria included birth asphyxia; infants of mothers with hypertension, preeclampsia, gestational diabetes, type 1 diabetes mellitus or illicit substance use; major congenital anomaly. BP measurements were determined using the oscillometric technique with the neonate supine after an appropriate size cuff was applied on the right arm. Multichannel monitor was used to determine systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP) by oscillometric method ( ANSI/AAMI SP-10/2002 Memory 500 Records IBP 2 Channels(Up to 4) . Systolic and diastolic BPs were statistically analyzed by regression analysis for various percentiles (5th to 95th).Results: This is made up of 185 (57.8 %) males and 135 (42.2 %) females with M: F ratio of 1.36:1.Birth weight ranged from 1650-4650 gr (mean = 2058.3 ±852.5 gr). GA ranged from 26- 42 weeks (mean = 32.95± 3.97 weeks) .Two hundred and twenty one (69.1 %) babies were delivered through cesarean section and 99 (30.9 %) deliveries were by vaginal delivery. Percentile charts (providing 5th, 10th, 25th, 50th, 75th, 95th values) have been developed. SBP, DBP and MAP showed a steady rise on the respective days that were comparable between different groups. Evidently, there were no statistically significant gender differences in mean body weight, gestational age and the BP parameters. Term babies were found to have higher SBP, DBP and MAP than their preterm counterparts on the respective days that were statistically highly significant. Neonates who were delivered vaginally had higher mean BP values for systolic, diastolic and mean than neonates delivered by cesarean section. There were no statistically significant difference in mean SBP, DBP and MAP recordings between males and females. However Female neonates had higher systolic BP values than male neonates.Conclusion: The study provided normative BP values among neonates especially in the first 7 days of life. These values are recommended for use in the evaluation of BP in newborns. Data presented in this study mode specific BP percentile curves using an oscillometric method and serve as a valuable reference for physicians in dealing with the management of newborns in the neonatal unit.