Objectives: To study the influence of umbilical cord milking versus delayed cord clamping on the early prognosis of preterm infants with a gestational age of <34 weeks.
Methods: PubMed, Web of Science, Embase, the Cochrane Library, CINAHL, China National Knowledge Infrastructure, Wanfang Data, Weipu Database, and SinoMed were searched for randomized controlled trials on umbilical cord milking versus delayed cord clamping in preterm infants with a gestational age of <34 weeks published up to November 2021. According to the inclusion and exclusion criteria, two researchers independently performed literature screening, quality evaluation, and data extraction. Review Manger 5.4 was used for Meta analysis.
Results: A total of 11 articles were included in the analysis, with 1 621 preterm infants in total, among whom there were 809 infants in the umbilical cord milking group and 812 in the delayed cord clamping group. The Meta analysis showed that compared with delayed cord clamping, umbilical cord milking increased the mean blood pressure after birth (weighted mean difference=3.61, 95%CI: 0.73-6.50, P=0.01), but it also increased the incidence rate of severe intraventricular hemorrhage (RR=1.83, 95%CI: 1.08-3.09, P=0.02). There were no significant differences between the two groups in hemoglobin, hematocrit, blood transfusion rate, proportion of infants undergoing phototherapy, bilirubin peak, and incidence rates of complications such as periventricular leukomalacia and necrotizing enterocolitis (P>0.05).
Conclusions: Compared with delayed cord clamping, umbilical cord milking may increase the risk of severe intraventricular hemorrhage in preterm infants with a gestational age of <34 weeks; however, more high-quality large-sample randomized controlled trials are needed for further confirmation.
目的: 分析脐带挤压与延迟断脐对胎龄<34周早产儿早期预后的影响。方法: 计算机检索PubMed、Web of Science、Embase、Cochrane Library、CINAHL、中国知网、万方数据库、维普数据库和中国生物医学文献服务系统数据库从建库到2021年11月发表的胎龄<34周早产儿脐带挤压与延迟断脐的随机对照试验。由2名研究人员根据纳入和排除标准，独立对文献进行筛选和质量评价，并提取数据，采用Review Manger 5.4进行Meta分析。结果: 最终纳入11篇文献，共1 621例早产儿，其中脐带挤压组809例，延迟断脐组812例。Meta分析结果显示，与延迟断脐相比，脐带挤压提高了早产儿出生后平均血压（WMD=3.61，95%CI：0.73~6.50，P=0.01），但增加了早产儿严重脑室内出血的发生率（RR=1.83，95%CI：1.08~3.09，P=0.02），两者在早产儿出生后血红蛋白水平、红细胞压积、输血率、光疗率、血清胆红素峰值及脑室周围白质软化、坏死性小肠结肠炎等并发症发生的影响差异均无统计学意义（P>0.05）。结论: 与延迟断脐相比，脐带挤压可能增加胎龄<34周早产儿严重脑室内出血的风险，但仍需更多高质量、大样本的随机对照试验进一步证实。.
Keywords: Delayed cord clamping; Intraventricular hemorrhage; Meta analysis; Placental transfusion; Preterm infant; Umbilical cord milking.