Abstract: We included six studies that compared early oropharyngeal colostrum versus water, saline, placebo, or donor, or versus no intervention, enrolling 335 preterm infants with gestational ages ranging from 25 to 32 weeks' gestation and birth weights of 410 to 2500 grams. Researchers found no significant differences between OPC and control for primary outcomes - incidence of NEC (typical risk ratio (RR) 1.42, 95% confidence interval (CI) 0.50 to 4.02; six studies, 335 infants; P = 0.51; I² = 0%; very low-quality evidence), incidence of late-onset infection (typical RR 0.86, 95% CI 0.56 to 1.33; six studies, 335 infants; P = 0.50; I² = 0%; very low-quality evidence), and death before hospital discharge (typical RR 0.76, 95% CI 0.34 to 1.71; six studies, 335 infants; P = 0.51; I² = 0%; very low-quality evidence). Similarly, meta-analysis showed no difference in length of hospital stay between OPC and control groups (mean difference (MD) 0.81, 95% CI -5.87 to 7.5; four studies, 293 infants; P = 0.65; I² = 49%). Days to full enteral feeds were reduced in the OPC group with MD of -2.58 days (95% CI -4.01 to -1.14; six studies, 335 infants; P = 0.0004; I² = 28%; very low-quality evidence). The effect of OPC was uncertain because of small sample sizes and imprecision in study results (very low-quality evidence). No adverse effects were associated with OPC; however, data on adverse effects were insufficient, and no numerical data were available from the included studies. Overall the quality of included studies was low to very low across all outcomes. We downgraded GRADE outcomes because of concerns about allocation concealment and blinding, reporting bias, small sample sizes with few events, and wide confidence intervals. Large, well-designed trials would be required to evaluate more precisely and reliably the effects of oropharyngeal colostrum on important outcomes for preterm infants.

Plain-language summary: We searched for both published and unpublished studies comparing oropharyngeal colostrum versus a control such as water, placebo, or no oral priming. We included only clinical trials reporting outcomes in preterm babies (< 37 weeks' gestation). The evidence is up-to-date as of August 2017. We did not limit the review to any particular region or language. Six studies were eligible for inclusion, involving 335 preterm infants with gestational ages ranging from 25 to 32 weeks' gestation and birth weights of 410 to 2500 grams. Reviewers noted no differences between OPC and control for rate of NEC, infection, or death before hospital discharge. Similarly, they observed no difference in length of hospital stay between OPC and control babies. Infants who received OPC achieved full milk feeds on average 2.5 days earlier than those given placebo or no intervention. However, included studies were small, data were insufficient, and study designs were not ideal. Combining study data did not provide sufficient evidence to recommend the use of colostrum for oral priming to prevent complications in preterm infants. Five of the included studies reported no harms (adverse effects); however, no numerical data are available from these studies. Included studies were of very low quality; therefore the effects of OPC remain uncertain. Larger, better quality clinical trials would be needed to evaluate more precisely and reliably the effects of OPC on important outcomes for preterm infants. .