Objective The past 2 decades have witnessed an increased survival of extremely low gestational age (ELGA; 23–27 weeks GA) infants who are exposed to multiple painful procedures at a time of rapid neurological development. Pain in the developing nervous system differs from the mature nervous system, but little is known about how ELGA infants manifest pain. The aim is to systematically review the evidence of pain in ELGA infants to ascertain best pain practices.

Methods A comprehensive electronic search was conducted in MEDLINE, CINAHL and EMBASE. Two individuals screened and extracted data independently from relevant papers.

Results Only 3/13 papers focused on pain behaviors in ELGA neonates. In 2 studies, ELGA infants were examined during painful and non-painful situations. Increased facial actions and decreased body movement were indicators of pain, but magnitude of response was proportional to gestational age (GA). One study contributed to the construct validity of the Premature Infant Pain Profile, while a second contributed to the validity of a non-English version with more mature infants. Seven studies examined ELGA infants at 32 weeks GA; however pain stimuli (e.g. heel lance, clustered care) and outcome measures (e.g. facial, body movement) varied. Only one study examined the maturational effects on pain responses in 11 neonates.

Conclusions Few studies have examined pain behaviors in ELGA, and most were derived from small sample sizes with single observations during heel lance procedures. Further longitudinal studies with adequate sample sizes examining a broad repertoire of responses for a variety of pain paradigms is required.