Objective: To systematically evaluate the effect of colostrum on immunoglobulin A (IgA) levels among premature infants, so as to provide the evidence for improving premature infants' health with colostrum feeding. Methods: Randomized controlled clinical trials (RCTs) or controlled clinical trials (CCTs) pertaining to the effect of colostrum and IgA levels among premature infants were retrieved in national and international databases from inception to September 30, 2022, including CNKI, Wanfang Data, PubMed and Web of Science. Standardized mean difference (SMD) was used as an effect index for meta-analysis. The robustness of the results was evaluated using sensitivity analysis, and the publication bias was evaluated using Begg's test, Egger's test and funnel plot. Results : A total of 650 publications were retrieved initially, and 10 studies were finally included, including 9 RCTs and one1 CCT, with 677 participants. Meta-analysis showed higher secretory salivary secretory IgA levels among premature infants with colostrum feeding than among controls (SMD=0.49, 95%CI: 0.08-0.89), and there were no significant differences between groups in terms of urinary secretory IgA levels (SMD=0.19, 95%CI: -0.39-0.77) or blood IgA levels (SMD=0.29, 95%CI: -0.01-0.59). Sensitivity analysis showed robustness of meta-analysis results, and no publication bias was examined. Conclusion Colostrum feeding may increase salivary secretory IgA levels among premature infants; however, it has no effect on urine salivary secretory IgA levels or blood IgA levels.

Objective:To observe the effect of breastfeeding on the incidence of retinopathy of prematurity (ROP).Methods:A retrospective clinical study. From June 2017 to December 2019, 1256 eyes of 628 premature infants who were born in Ningbo Women and Children's Hospital and were screened for ROP were included in the study. Among them, there were in 325 males (650 eyes) and 303 females (606 eyes). According to the feeding situation, premature infants were divided into breastfeeding (research) group and formula feeding (control) group, with 390 cases of 780 eyes and 238 cases of 476 eyes, respectively. The changes in the retina of the fundus of the two groups of premature infants during the observation period were compared. The qualitative data comparison between groups was performed by the χ2 test; the quantitative data comparison was performed by the two independent sample t test. Results:The sex ratio of premature infants in the study group and control group ( χ2=0.217), birth weight ( t=0.728), gestational age at birth ( t=0.351), Apgar score at birth ( t=0.816), oxygen inhalation time ( t=0.427), were compared with the length of stay in the neonatal intensive care unit ( t=1.580), the difference was not statistically significant ( P>0.05). Among the 390 cases in the study group, 108 cases (27.7%, 108/390) and 282 cases (72.3%, 282/390) were with or without ROP, respectively; in the 238 cases in the control group, 86 (36.1%, 86/238) were with ROP, 152 (63.9%, 152/238) cases were without ROP. There was a statistically significant difference in the incidence of ROP between the two groups ( χ2=4.934, P=0.026). Among the 108 cases of ROP in the study group, 50 (12.8%, 50/108), 35 (9.0%, 35/108), 23 (5.9%, 23/108) cases were in stage 1, 2 and 3, respectively. Among the 86 ROP cases in the control group, stages 1, 2 and 3 were 25 (10.5%, 25/86), 40 (16.8%, 40/86), and 21 (8.8%, 21/86), respectively. In the comparison of ROP staging between the two groups, the difference in stage 1 was not statistically significant ( χ2=0.754, P>0.05), and the difference in stage 2 and above was statistically significant ( χ2=11.400, P<0.05). Conclusion:Breastfeeding may reduce the incidence and severity of ROP.