Related Experiment Video
Updated: Aug 7, 2026
Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale
Published on: August 25, 2014
Preterm infant behavioral and heart rate responses to antenatal phenobarbital
G C McCain1, E F Donovan, P Gartside
1Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
Insights
Antenatal phenobarbital did not sedate preterm infants. Behavioral changes, not heart rate, better indicated infant distress during caregiving.
Area of Science:
- Neonatal care
- Developmental pediatrics
- Pharmacology
Background:
- Antenatal medication use in preterm infants requires careful assessment of potential effects.
- Phenobarbital is sometimes used antenatally, but its impact on neonatal behavior needs clarification.
Purpose of the Study:
- To evaluate the effects of antenatal phenobarbital on behavioral state and heart rate in preterm infants.
- To determine if antenatal phenobarbital has a sedative effect on neonates.
Main Methods:
- Randomized controlled trial involving 49 preterm infants (24-34 weeks postconceptional age).
- Behavioral state and heart rate were observed during routine caregiving on days 1-3 of life.
- Comparison between infants exposed to antenatal phenobarbital and a control group.
Main Results:
- No significant differences in behavioral state or heart rate responses were observed between the phenobarbital and control groups.
- Infants in both groups exhibited behavioral changes (fussy/cry) and increased heart rate during caregiving.
- Older and non-ventilated infants showed more fussy/cry states compared to younger and ventilated infants.
Conclusions:
- Antenatal phenobarbital does not appear to cause a sedative effect in preterm infants.
- Behavioral responses, rather than heart rate, may be a more sensitive indicator of distress in very preterm infants during caregiving procedures.
- Routine caregiving elicits physiological and behavioral responses in preterm neonates.
Abstract:
The effects of antenatal phenobarbital on behavioral state and heart rate (HR) were examined in a randomized sample of 49 preterm infants > 24 and < 34 weeks postconceptional age. Behavioral state and HR observations were made during a routine care giving procedure on Days 1, 2, and 3 of life. There were no differences in behavioral state and HR responses between control and experimental subjects, suggesting that antenatal phenobarbital did not have a sedative effect on experimental subjects. Infants in both study groups responded to caregiving with changes to fussy/cry behavior and increases in HR. Older infants and nonventilated infants were more often in fussy/cry states during care giving than younger infants and ventilated infants. The HR increases were not clinically important, but the behavioral changes were, suggesting that behavioral response may be a more sensitive sign of distress than HR in very young preterm infants.
