Blood Pressure Reference Values of Nigerian Full-term Neonates in the First Week of Life at a Nigerian Tertiary Hospital: A Cross-sectional Survey

Introduction: Knowledge of normative Blood Pressures (BP) is critical for appropriate neonatal care. Hypertension and hypotension are abnormalities of BP which could be a sign, outcome or complications of diseases or intervention carried out on neonates. Yet, there is a dearth of data on BP concerning Nigerian full-term neonates.

Aim: To determine BP values of apparently healthy term Nigerian neonates in relation to their weight in the first eight days of life and also to determine the BP values of apparently healthy term neonates in the first eight days and also to correlate the BP with postnatal age, weight and to generate percentile of age/sex specific BP.

Materials and Methods: This cross-sectional study was done from September 2012-April 2013, including 386 consecutive apparently healthy term newborns delivered at the UNIOSUN Teaching Hospital (UTH), Osogbo, Southwest Nigeria. Their weights and right arm Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP) and Mean Arterial Pressure (MAP) BPs measured using oscillometric method on days 1, 3, 5 and 8. Student’s t-test and Pearson correlation coefficient was used to statistically analyse the data.

Results: Out of 386 newborns studied, the mean birth weight were 3.10±0.38 kg; {3.24±0.37 kg for boys and 2.97±0.33 kg for girls}. The mean values of SBP on day 1 were 67.3±5.6 mmHg; 71.0±6.0 mmHg on day 3; 73.8±5.2 mmHg on day 5 and 77.2±2.9 mmHg on day 8, respectively. A similar trend was also noticed in the mean values of DBP with 36.9±5.0 mmHg on day 1; 41.5±5.2 mmHg on day 3; 43.7±5.3 mmHg on day 5 and 46.4±4.7 mmHg on day 8, respectively, the rise being significant (p-value <0.001). There were a positive correlations between the weight and DBP on the 5th day (r=0.128; p-value=0.012), between weight and SBP at 49-72 hours and on day 8 (r=0.105; r=0.168, respectively) as well as weight and MAP on day 8 (r=0.166).

Conclusion: Neonatal BP in the first eight days following birth correlated positively to weight and age without significant gender differences.