Related Experiment Video
Updated: Mar 19, 2026
A Preterm Rat Model for Pain Studies
Published on: February 9, 2024
Pain-Related Reactions among Premature Infants with Gestational Age Less than 26 Weeks: An Observational Cohort Study
Kyriakos Martakis1, Christoph Hünseler, Kruthika Thangavelu
1Children's and Adolescents' Hospital, University Hospital of Cologne, Cologne, Germany.
Insights
Very premature infants (less than 26 weeks gestational age) show distinct pain reactions within 72 hours of birth. Experienced neonatal intensive care unit (NICU) staff can reliably assess these infant pain responses.
Area of Science:
- Neonatal care
- Pediatric pain research
Background:
- Limited data exists on acute pain reactions in extremely premature infants (<26 weeks gestational age).
- No validated pain measurement scale is available for this vulnerable population.
Purpose of the Study:
- To investigate specific pain reactions in premature infants with gestational age <26 weeks.
- To hypothesize and identify observable pain responses within the first 72 hours of life.
Main Methods:
- Prospective, observational study using mixed methods.
- Filming of routine blood draws (capillary or peripheral).
- Analysis of videos by experienced neonatal intensive care unit (NICU) staff using a defined behavioral model.
Main Results:
- Nineteen of twenty infants (gestational age 22w3d-26w) exhibited pain reactions.
- Common reactions included eye movements, altered breathing patterns, and increased SpO2.
- High interrater and intrarater reliability was achieved in video analysis.
Conclusions:
- Extremely premature infants (<26 weeks) display discernible reactions to pain stimuli within 72 hours of birth.
- Experienced NICU staff can reliably evaluate these pain responses.
Introduction:
There is insufficient information regarding acute pain reactions among premature infants with a gestational age of less than 26 weeks and no appropriate scale for pain measurement in this age group. We hypothesized that these infants present specific reactions to a standardized pain stimulus within the first 3 days of life.
Methodology:
Mixed-methods, prospective, open-label, single-arm, observational study. Routine capillary or peripheral blood takes were filmed. The model consisting of a baseline, a preparatory, an interventional and a return-to-baseline phase was filmed. After a pilot evaluation, experienced medical and nursing neonatal intensive care unit (NICU) staff analysed the videos.
Results:
Twenty infants with gestational ages ranging from 22 weeks and 3 days to 26 weeks (mean 24 weeks) were recruited. Nineteen infants showed pain reactions, with a mean latency of 8.3 s (range 2-30). The majority presented eye movements, changes of the breath pattern and a slight increase in the mean SpO2 value. A high degree of interrater and intrarater reliability was found.
Discussion:
Premature infants with a gestational age of up to 26 weeks can present a variety of discrete reactions as response to a pain stimulus within the first 72 h of life. Experienced NICU staff can perform a valid and reliable evaluation of these reactions.
