ABSTRACT Aim This study evaluated poor weight gain as a risk factor for infants who required treatment for retinopathy of prematurity (ROP), by comparing those born before and after the implementation of higher oxygen saturation (SpO2) targets at the Queen Silvia Children's Hospital, Gothenburg, Sweden. Methods: We compared infants born at less than 31 weeks, who were screened and, or, treated for ROP: 127 in 2011–2012 when SpO2 targets were 88–92% and 142 in 2015–2016 when they were 91–95%. The subjects were reviewed for birth characteristics, weekly weight and ROP treatment. Data were analysed using the weight, insulin‐like growth factor 1, neonatal, ROP (WINROP) prediction tool. Results: The 2011–2012 infants who needed ROP treatment (12.6%) had significantly poorer postnatal weight gain than those who did not, but this was not seen in the treated (17.6%) and nontreated ROP groups in 2015–2016. WINROP sensitivity decreased from 87.5% in 2011–12 to 48% in 2015–2016. Conclusion: After the SpO2 target range was increased from 88–92% to 91–95%, postnatal weight gain was no longer a significant risk factor and WINROP lost its ability to predict ROP requiring treatment. Risk factors clearly change as neonatal care develops
