title: Cardiovascular transition at birth: a physiological sequence.
abstract: The transition to newborn life at birth involves major cardiovascular changes that are triggered by lung aeration. These include a large increase in pulmonary blood flow (PBF), which is required for pulmonary gas exchange and to replace umbilical venous return as the source of preload for the left heart. Clamping the umbilical cord before PBF increases reduces venous return and preload for the left heart and thereby reduces cardiac output. Thus, if ventilation onset is delayed following cord clamping, the infant is at risk of superimposing an ischemic insult, due to low cardiac output, on top of an asphyxic insult. Much debate has centered on the timing of cord clamping at birth, focusing mainly on the potential for a time-dependent placental to infant blood transfusion. This has prompted recommendations for delayed cord clamping for a set time after birth in infants not requiring resuscitation. However, recent evidence indicates that ventilation onset before cord clamping mitigates the adverse cardiovascular consequences caused by immediate cord clamping. This indicates that the timing of cord clamping should be based on the infant's physiology rather than an arbitrary period of time and that delayed cord clamping may be of greatest benefit to apneic infants.
authors: 1] The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, Australia [2] Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia.
authors: Stuart B
authors: SB
authors: Hooper
authors: Department of Pediatrics, Leiden University Medical Centre, Leiden, The Netherlands.
authors: Arjan B
authors: AB
authors: Te Pas
authors: The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, Australia.
authors: Justin
authors: J
authors: Lang
authors: Department of Pediatrics, Leiden University Medical Centre, Leiden, The Netherlands.
authors: Jeroen J
authors: JJ
authors: van Vonderen
authors: 1] The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, Australia [2] Monash Newborn, Monash Medical Centre, Clayton, Victoria, Australia.
authors: Charles Christoph
authors: CC
authors: Roehr
authors: Department of Neonatalogy, Royal North Shore Hospital and University of Sydney, Sydney, New South Wales, Australia.
authors: Martin
authors: M
authors: Kluckow
authors: Centre for Neonatal Research and Education, The University of Western Australia, Perth, Western Australia, Australia.
authors: Andrew W
authors: AW
authors: Gill
authors: 1] The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, Australia [2] Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia.
authors: Euan M
authors: EM
authors: Wallace
authors: 1] The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, Australia [2] Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia.
authors: Graeme R
authors: GR
authors: Polglase
mesh_terms: D001783:Blood Flow Velocity; D002302:Cardiac Output; D002318:Cardiovascular Diseases / Q000503:physiopathology; D002320:Cardiovascular Physiological Phenomena; D002319:Cardiovascular System; D003250:Constriction; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007231:Infant, Newborn; D036801:Parturition; D010920:Placenta / Q000502:physiology; D021041:Placental Circulation; D011247:Pregnancy; D011652:Pulmonary Circulation; D011659:Pulmonary Gas Exchange; D013997:Time Factors; D014470:Umbilical Cord / Q000502:physiology