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Published on: December 31, 2015
Postnatal blood pressure in the preterm small for gestational age neonate
Samantha Dizon1, Suma Bhat Hoffman1
1Department of Pediatrics, University of Maryland Baltimore, School of Medicine, Baltimore, MD, USA.
Insights
Blood pressure in premature infants small for gestational age (SGA) initially matches appropriate for gestational age (AGA) peers but then diverges. SGA infants’ blood pressure fails to increase at the same rate as AGA infants after 24 hours.
Area of Science:
- Neonatal physiology
- Perinatal medicine
- Pediatric cardiology
Background:
- Premature infants born small for gestational age (SGA) present unique physiological challenges.
- Understanding blood pressure regulation in SGA neonates is crucial for clinical management and long-term outcomes.
- Gestational age (GA) and birth weight (BW) are key determinants of neonatal hemodynamics.
Purpose of the Study:
- To investigate the differences in mean arterial blood pressure (MAP) between premature infants born small for gestational age (SGA) and appropriate for gestational age (AGA).
- To analyze the temporal changes in MAP in SGA infants compared to AGA infants during the first 96 hours of life.
- To identify factors influencing MAP in this vulnerable population.
Main Methods:
- Retrospective study of inborn infants aged 24-32 weeks gestation.
- Mean arterial blood pressure (MAP) was recorded and averaged every 12 hours for the initial 96 hours of life.
- Statistical analysis included t-tests for group comparisons and linear mixed-effects modeling to account for GA, BW, gender, and SGA status.
Main Results:
- Out of 356 infants, 52 (14.6%) were SGA. SGA infants were smaller, more likely male, and had higher rates of maternal hypertension, C-section delivery, chronic lung disease, and retinopathy of prematurity.
- SGA infants' MAP closely mirrored AGA infants' MAP for the first 24 hours.
- After 24 hours, SGA infants exhibited lower MAPs, aligning more with weight-matched counterparts. GA was a significant predictor (p < 0.0001), while BW showed marginal significance (p = 0.049).
Conclusions:
- Blood pressure in SGA infants is strongly associated with gestational age in the first 24 hours.
- Following the initial 24 hours, SGA infants' blood pressure fails to increase at the same rate as their AGA counterparts.
- These findings highlight distinct hemodynamic trajectories in SGA premature infants requiring further investigation.
Objective:
Determine how blood pressure differs in premature infants born small for gestational age (SGA).
Design:
A retrospective study was conducted on inborn infants 24-32 weeks gestation. Mean arterial blood pressure (MAP) was collected and averaged every 12 h for the first 96 h of life. For each time point, the difference MAP in SGA vs. AGA infants was evaluated with t-testing. Linear mixed-effects modeling was performed to model MAP over time accounting for GA, BW, gender, and SGA status.
Results:
356 subjects were evaluated. 52 (14.6%) were SGA. SGA infants were smaller, more likely male, exposed to maternal hypertension, born via caesarian section, and have chronic lung disease and retinopathy of prematurity. MAP in the SGA group more closely matched the MAP of AGA babies of similar GA for the first 24 h of life. Subsequently, SGA infants had lower MAPs more closely resembling their weight-matched counterparts. Mixed modeling showed GA to be significant, p < 0.0001 while BW though still marginally significant had less of an effect, p = 0.049.
Conclusion:
SGA infants have blood pressure that is strongly associated with GA in the first 24 hours of life, but then fails to increase at the same rate as their AGA counterparts.
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