Key messages
Clinical staff should be aware that the available rating scales for assessing pain in newborn infants are of very low quality. There is a need to develop these scales further.

What are clinical rating scales?
Since newborn infants cannot express their pain with words, staff need to assess their pain by looking at their behaviours and vital signs instead. Many different rating scales can be used for this, assessing infant pain through, for example, heart frequency, facial expression, and body movement.

What did we want to find out?
We wanted to describe the existing rating scales and assess their quality.

What did we do?
We searched databases for studies that had developed or tested a rating scale for assessing pain in newborn infants.

What did we find?
We included 79 studies involving a total of 7197 infants, 326 nurses, and 12 doctors. Twenty-seven different rating scales were used in the studies. Our evaluation found all rating scales to be of very low quality.

What are the limitations of the evidence?
Although the number of included studies was relatively high, the evidence was scattered across the vast number of included clinical pain-rating scales and the different methodological aspects that we intended to measure. This resulted in only a few studies being available for each separate aspect of our measurements. Evidence for the most important methodological aspects of the rating scales was of very low quality, preventing any strong conclusions.

How up-to-date is this evidence?
The evidence is current to July 2023.