Chaowawanit Woraphot, Koovimon Pruk, Soongsatitanon Adjima
Department of Obstetrics and Gynecology, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand.
J Obstet Gynaecol. 2020 Feb;40(2):205-210. doi: 10.1080/01443615.2019.1621812. Epub 2019 Aug 8.
Umbilical cord milking is an alternative procedure providing blood to infants but there is no study in the proper length of umbilical cord and various gestational age. The aim of this study was to measure the blood volume in the umbilical cord of preterm infants at a certain length and to identify the correlation among blood volume, length, and circumference of umbilical cord, gestational age (GA), birth weight and placenta. Seventy-five pregnant women aged 18 years old and above with 24-36 weeks of gestation were included in this cross-sectional study. After delivery, a 15 to 45 cm of umbilical cord was cut and parameters of umbilical cord were recorded. The mean GA at birth was 241.84 ± 20.06 days. The mean length, diameter, and circumference were 23.31 ± 7.66, 1.10 ± 0.18, and 3.56 ± 0.75 cm, respectively. The mean residual blood volume was 11.58 ± 4.99 mL or 0.50 ± 0.18 mL/cm. Total residual blood volume had a significant positive strong correlation with umbilical cord length ( = 0.720, < .001). To reduce complications from blood overload, the appropriate blood volume for preterm infant should be calculated from birth weight and umbilical cord length.Impact statement The World Health Organisation recommends delayed cord clamping for newborn infants which neonatal resuscitation was not indicated but the majority of preterm infants needed resuscitation. Umbilical cord milking is an alternative procedure providing blood to infants. A small volume transfusion (10-20 m/kg) is commonly used for replacement in preterm neonates. Although there is a concern about the blood volume transferred into infants, blood volume and proper length of umbilical cord have not been thoroughly investigated. In this study, the mean residual blood volume was 0.5 mL/cm and total residual blood volume had a significant positive strong correlation with umbilical cord length. In subgroup of very low birth weight group, the mean residual blood volume was 0.41 mL/cm; however, there was no statistically significant difference from other birth weight groups. The appropriate length of umbilical cord for milking can be calculated from the estimated foetal weight and the mean residual blood volume per length (0.5 mL/cm); nevertheless, the calculation should be used with caution. The further study should investigate in extremely preterm or very low birth weight infants.
脐带挤血是一种为婴儿提供血液的替代方法，但尚无关于脐带合适长度及不同孕周的研究。本研究旨在测量一定长度的早产儿脐带中的血量，并确定血量与脐带长度、周长、孕周（GA）、出生体重及胎盘之间的相关性。本横断面研究纳入了75名年龄18岁及以上、孕周为24 - 36周的孕妇。分娩后，截取15至45厘米长的脐带并记录脐带参数。出生时的平均孕周为241.84 ± 20.06天。平均长度、直径和周长分别为23.31 ± 7.66厘米、1.10 ± 0.18厘米和3.56 ± 0.75厘米。平均残余血量为11.58 ± 4.99毫升或0.50 ± 0.18毫升/厘米。总残余血量与脐带长度呈显著正强相关（r = 0.720，P <.001）。为减少血容量过载的并发症，应根据出生体重和脐带长度计算早产儿的合适血量。影响声明 世界卫生组织建议对无需新生儿复苏的新生儿延迟脐带结扎，但大多数早产儿需要复苏。脐带挤血是一种为婴儿提供血液的替代方法。小容量输血（10 - 20毫升/千克）常用于早产儿的替代治疗。尽管人们担心输入婴儿体内的血量，但血量及脐带的合适长度尚未得到充分研究。在本研究中，平均残余血量为0.5毫升/厘米，总残余血量与脐带长度呈显著正强相关。在极低出生体重组亚组中，平均残余血量为0.41毫升/厘米；然而，与其他出生体重组相比无统计学显著差异。可根据估计胎儿体重和每厘米平均残余血量（0.5毫升/厘米）计算挤血所需的合适脐带长度；不过，计算时应谨慎使用。进一步的研究应针对极早产儿或极低出生体重儿展开。
