Introduction: Premature birth is one of the major challenges for health systems worldwide. Premature infants require transfer to receive specialized care, and this transfer is associated with short-term and long-term complications. Transfer of premature infants to the neonatal intensive care unit (NICU) is associated with physical and acoustic stimuli on the vital signs of the infants.

Objective: This study aimed to determine the effect of developmental care on the vital signs of premature infants during intra hospital transfer to one of the hospitals in Tehran in 1404.

Materials and Methods: The present study is a two-group randomized clinical trial, which was conducted on 78 premature infants transferred from the operating room or delivery block to the NICU. The experimental group received developmental care (incubation cover, nest, pacifier, swaddling, hat). The control group received usual care. The research tools included a demographic information checklist and a vital sign recording form. The data were analyzed using SPSS software version 24 and Fisher's exact test, Mann-Whitney, independent t-test, and chi-square test, and (P<0.05) was considered as a significant level.

Findings: In this study, after the intervention, there was no significant difference between the groups in temperature, heart rate, respiratory rate, and blood pressure (P> 0.05). For oxygen saturation, it was significantly higher in the test group before the intervention (P= 0.022). After adjusting for baseline with ANCOVA, the difference was not significant (P= 0.142). However, the test group showed less fluctuation and greater relative stability in vital signs.

Discussion and Conclusion: This study did not show a statistically significant effect of developmental care on the vital signs of premature infants in short-term inpatient transfer. However, the overall trend was towards relative stability of vital signs in the test group. This low-cost and safe intervention could be supportive, but larger studies with longer follow-up and better control for baseline differences are needed to confirm efficacy.