What does the evidence tell us? Revisiting optimal cord management at the time of birth

European Journal of Pediatrics https://doi.org/10.1007/s00431-022-04395-x REVIEW What does the evidence tell us? Revisiting optimal cord management at the time of birth Heike Rabe1 · Judith Mercer2,3 · Debra Erickson‑Owens3 Received: 3 November 2021 / Revised: 12 January 2022 / Accepted: 22 January 2022 © The Author(s) 2022 Abstract A newborn who receives a placental transfusion at birth from delayed cord clamping (DCC) obtains about 30% more blood volume than those with immediate cord clamping (ICC). Benefits for term neonates include higher hemoglobin levels, less iron deficiency in infancy, improved myelination out to 12 months, and better motor and social development at 4 years of age especially in boys. For preterm infants, benefits include less intraventricular hemorrhage, fewer gastrointestinal issues, lower transfusion requirements, and less mortality in the neonatal intensive care unit by 30%. Ventilation before clamping the umbilical cord can reduce large swings in cardiovascular function and help to stabilize the neonate. Hypovolemia, often associated with nuchal cord or shoulder dystocia, may lead to an inflammatory cascade and subsequent ischemic injury. A sudden unexpected neonatal asystole at birth may occur from severe hypovolemia. The restoration of blood volume is an important action to protect the hearts and brains of neonates. Currently, protocols for resuscitation call for ICC. However, receiving an adequate blood volume via placental transfusion may be protective for distressed neonates as it prevents hypo‑ volemia and supports optimal perfusion to all organs. Bringing the resuscitation to the mother’s bedside is a novel concept and supports an intact umbilical cord. When one cannot wait, cord milking several times can be done quickly within the resuscitation guidelines. Cord blood gases can be collected with optimal cord management. Conclusion: Adopting a policy for resuscitation with an intact cord in a hospital setting takes a coordinated effort and requires teamwork by obstetrics, pediatrics, midwifery, and nursing. What is Known: • Placental transfusion through optimal cord management benefits morbidity and mortality of newborn infants. • The World Health Organisation has recommended placental transfusion in their guidance. What is New: • Improved understanding of transitioning to extrauterine life has been described. • Resuscitation of newborn infants whilst the umbilical cord remains intact could improve the postpartum adaptation. Keywords Placental blood · Newborn · Postpartum adaptation · Cord clamping · Cord milking Abbreviations DCC Delayed cord clamping ICC Immediate cord clamping Communicated by Daniele De Luca. ILCOR International Liaison Committee for Resuscitation IVH Intraventricular hemorrhage NICU Neonatal intensive care unit NRP Neonatal Resuscitation Program OCM Optimal cord management 1 Brighton and Sussex Medical School, University of Sussex, Brighton, UK Judith Mercer 2 Neonatal Research Institute at Sharp Mary Birch Hospital for Women and Newborns, San Diego, CA, USA Debra Erickson‑Owens 3 College of Nursing, University of Rhode Island, Kingston, RI, USA * Heike Rabe 13 Vol.:(0123456789) European Journal of Pediatrics PVR Pulmonary vascular resistance UCM Umbilical cord milking WHO World Health Organization Introduction During pregnancy, fetal blood circulates between the fetus and the placenta providing essential nutrients and oxygen. At delivery, infants undergo rapid changes in Circulation and breathing in order to adapt to extra-uterine life. Optimal cord management (OCM), involving waiting several minutes before clamping and cutting the cord has been shown to increase circulatory stability and reduce in-hospital mor‑ tality [1–3]. Or if unable to wait, gently milking the cord towards the infant provides some placental transfusion and is preferable over immediate cord clamping (ICC) [3]. The different methods of OCM are listed in Table 1. The World Health Organization (WHO) has recommended delayed cord clamping (DCC) as standard practice at the delivery of all infants but implementation is still variable across health care settings and countries [4, 5]. We provide an overview of cur‑ rent knowledge about OCM and future perspectives. The physiology of placental transfusion What cord blood contains The residual placenta blood returns to the newborn warm (body temperature) and oxygenated. It contains about 15–20 mL/kg of red blood cells which provides the term infant with an adequate iron supply for four to 12 months [6, 7]. There are several million to a billion stem cells provid‑ ing an autologous transplant which may reduce the infant’s susceptibility to both neonatal and age-related diseases [8]. Progesterone is neuroprotective, and levels in the blood of term infants at birth are higher than the mother’s levels. This likely aids vasodilation and enhances the bodily distribu‑ tion of the large amount of placental transfusion [9, 10]. In addition, there are numerous additional components such as cytokines, growth factors, and important messengers in cord blood that most likely support and drive the process of transition but are too numerous to discuss here [11]. The full placental transfusion offers high pulmonary artery pressure in the first few hours of life to assist with neonatal adaptation [12]. It is likely that the force of the increased blood volume stimulates multi-organ perfusion for normal organ function, growth, and development. New research reveals that enhanced vascular perfusion causes an organ’s endothelial cells to release angiocrine responses to guide essential functions [13]. Circulation Throughout pregnancy, the fetal blood volume is approximately 110–115 mL/kg of fetal weight [14]. Only ~ 10% of the fetal cardiac output goes to the systemic circulation in the lungs, while 30 to 50% goes to the placenta where gas exchange takes place. In order to change from placental gas exchange to lung air exchange at birth, 45–50% of the newborn cardiac output must rapidly go into the alveolar capillary network in the lungs. Waiting to clamp the cord results in a net transfer of approxi‑ mately 30% of the fetal-placental blood volume over the first few minutes after birth from the placenta to the neonate. This provides the blood volume needed to fill the alveolar capillary network for the first time and to fully perfuse organs previously supported by the placenta [15]. Classic physiologic studies completed over the past 60 years have documented that placental transfusion results in improved perfusion in the neonate’s respiratory, hema‑ tologic, urinary, gastrointestinal, and neurological systems [16–18]. We have proposed that the blood volume received from a placental transfusion increases systemic and regional blood flow and vasodilation in the newborn and aids in nor‑ mal organ development and health. Immediate cord clamp‑ ing (ICC) reduces the neonate’s blood volume and (...truncated)