title: Delayed umbilical cord clamping at birth has effects on arterial and venous blood gases and lactate concentrations.
abstract: OBJECTIVE
  To estimate the influence of delayed umbilical cord clamping at birth on arterial and venous umbilical cord blood gases, bicarbonate (HCO3-), base excess (BE) and lactate in vigorous newborns.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Prospective observational.
  
  
  METHODS
  Vaginally delivered term newborns.
  
  
  METHODS
  Umbilical cord arterial and venous blood was sampled repeatedly every 45 seconds (T(0)= time zero; T(45)= 45 seconds, T(90)= 90 seconds) until the cord pulsations spontaneously ceased in 66 vigorous singletons with cephalic vaginal delivery at 36-42 weeks. Longitudinal comparisons were performed with the Wilcoxon signed-ranks matched pairs test. Mixed effect models were used to describe the shape of the regression curves.
  
  
  METHODS
  Longitudinal changes of umbilical cord blood gases and lactate.
  
  
  RESULTS
  In arterial cord blood, there were significant decreases of pH (7.24-7.21), HCO3- (18.9-18.1 mmol/l) and BE (-4.85 to -6.14 mmol/l), and significant increases of PaCO(2) (7.64-8.07 kPa), PO(2) (2.30-2.74 kPa) and lactate (5.3-5.9 mmol/l) from T(0) to T(90), with the most pronounced changes at T(0)-T(45). Similar changes occurred in venous blood pH (7.32-7.31), HCO3- (19.54-19.33 mmol/l), BE (-4.93 to -5.19 mmol/l), PaCO(2) (5.69-5.81 kPa) and lactate (5.0-5.3 mmol/l), although the changes were smaller and most pronounced at T(45)-T(90). No significant changes were observed in venous PO(2).
  
  
  CONCLUSIONS
  Persistent cord pulsations and delayed cord clamping at birth result in significantly different measured values of cord blood acid-base parameters.
authors.affiliation: Department of Obstetrics and Gynecology, Malmö University Hospital, University of Lund, Malmö, Sweden. nana.wiberg@med.lu.se
authors.forename: N
authors.initials: N
authors.lastname: Wiberg
authors.forename: K
authors.initials: K
authors.lastname: Källén
authors.forename: P
authors.initials: P
authors.lastname: Olofsson
mesh_terms: D000136:Acid-Base Equilibrium; D001639:Bicarbonates / Q000097:blood*; D001784:Blood Gas Analysis / Q000379:methods; D002245:Carbon Dioxide / Q000097:blood; D003250:Constriction; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn / Q000097:blood*; D019344:Lactic Acid / Q000097:blood*; D010100:Oxygen / Q000097:blood; D011247:Pregnancy; D011446:Prospective Studies; D013997:Time Factors; D014470:Umbilical Cord / Q000098:blood supply*
chemical_list: D001639:Bicarbonates; D002245:Carbon Dioxide; D019344:Lactic Acid; D010100:Oxygen