Objective:To analyze the time of recovery to the respiratory baseline after treatment of retinopathy of prematurity (ROP) and the possible influencing factors.Methods:The preterm infants with ROP who received ophthalmic treatment from January 2016 to December 2020 in the Department of Neonatology, Guangdong Women and Children′s Hospital were enrolled retrospectively.The baby who received vitreous injection were included in the injection group, and who received laser photocoagulation were included in the photocoagulation group.The patients were divided into two groups according to whether they returned to the respiratory baseline within 48 hours after ROP surgery.Relevant data were collected, including respiratory baseline, the respiratory status 24 hours, 48 hours, 72 hours, 96 hours, 5 days and 7 days after treatment, gestational age, birth weight, gender, corrected gestational age at surgery, weight at surgery, laser points, and treatment location.Wilcoxon signed-rank test was used for continuous variables. Data were expressed as the number and percentage of patients for categorical variables, using Chi-square test or Fisher′ s exact test. Binary Logistic regression analysis was used to analyze the influencing factors.The time taken by preterm infants to return to the preoperative respiratory baseline after treatment and its influencing factors were analyzed. Results:A total of 386 ROP infants were included in this study.There were 157 infants who did not return to the respiratory baseline within 48 hours after treatment.No significant difference in the source, gender, gestational age, birth weight, corrected gestational age at surgery, weight at surgery, and respiratory pressure support required before surgery were found between the group who returned to the respiratory baseline within 48 hours and the group who did not (all P>0.05). However, there were significant differences in treatment methods and location between two groups (all P<0.01). The ratio of returning to the respiratory baseline in the group receiving intravitreal injection was significantly different from that in the group treated with laser therapy at 24 h, 48 h, 72 h, and 96 h after treatment (77% vs.14%, 82% vs.33%, 86% vs.58%, 89% vs.76%; all P<0.01). There was no difference in that ratio between two groups at 5 d and 7 d after treatment (91% vs.86%, 95% vs.92%; P>0.05). Of the 157 infants who did not return to the respiratory baseline within 48 hours after treatment, 108 cases (68.8%) required additional supplemental oxygen, whereas 153 cases (98.5%) required more intensive respiratory support ( P<0.001). According to the multivariate Logistic regression analysis results, the preterm infants who received laser therapy were less likely to return to the respiratory baseline within 48 hours than those who received intravitreal injection ( OR=0.099, 95% CI: 0.060-0.164). A small corrected gestational age at surgery was an independent risk factor for infants not returning to the respiratory baseline within 48 hours ( OR=1.147, 95% CI: 1.009-1.302). Conclusions:Infants with ROP who receive intravitreal injection can return to the respiratory baseline more quickly than those who underwent laser photo-coagulation under. The difference persisted up to 4 days. The smaller the corrected gestational age at treatment, the less likely return to the respiratory baseline within 48 hours in photocoagulation group..