Advertisement

Association of umbilical cord blood gas values with mortality and severe neurologic injury in preterm neonates <29 weeks’ gestation: a national cohort study

Published:January 05, 2022DOI:https://doi.org/10.1016/j.ajog.2022.01.001

      Background

      Umbilical cord arterial and venous blood gas values reflect the acid-base balance status of a newborn at birth. Derangement in these values has been linked to poor neonatal outcomes in term and late preterm neonates; however, the utility of these values in preterm neonates of <29 weeks’ gestation is unclear.

      Objective

      This study aimed to determine the associations of umbilical cord arterial and venous blood gas values with neonatal mortality and severe neurologic injury in extremely preterm neonates and to identify the cutoff values associated with 2.5-fold increases or decreases in the posttest probabilities of outcomes.

      Study Design

      This was a retrospective cohort study of neonates who were born at 23+0 to 28+6 weeks’ gestation between January 1, 2018 and December 31, 2019, and who were admitted to neonatal units in Canada.

      Exposure

      Various cut-offs of umbilical cord blood gas values and lactate values were studied.

      Main Outcomes and Measures

      The main outcomes were mortality before discharge from the neonatal unit and severe neurologic injury defined as grade 3 or 4 periventricular or intraventricular hemorrhage or periventricular leukomalacia. The outcome rates were calculated for various cutoff values of umbilical cord blood gas parameters and were adjusted for birthweight, gestational age, sex, and multiple births. Likelihood ratios were calculated to derive posttest probabilities.

      Results

      A total of 1040 and 1217 neonates had analyzable umbilical cord arterial and venous blood gas values, respectively. In the cohort, the mean (standard deviation) gestational age was 26.5 (1.5) weeks, the mean birthweight was 936 (215) g, the prevalence of mortality was 10% (105/1040), and the prevalence of severe neurologic injury was 9% (92/1016). An umbilical cord arterial pH of ≤7.1 and base excess of ≤−12 mmol/L were associated with >2.5-fold higher posttest probability of mortality, and an umbilical cord arterial or venous lactate value of <3 was associated with a 2.5-fold lower posttest probability of mortality. An umbilical cord arterial lactate value of <3 was associated with a lower posttest probability of severe neurological injury.

      Conclusion

      In preterm neonates of <29 weeks’ gestation, low umbilical cord arterial pH and high umbilical cord arterial base excess values were associated with a clinically important increase in the posttest probability of mortality, whereas low umbilical cord arterial or venous lactate values were associated with a decrease in the posttest probability of mortality.

      Key words

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to American Journal of Obstetrics & Gynecology
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • ACOG Committee on Obstetric Practice
        ACOG Committee Opinion No. 348, November 2006: umbilical cord blood gas and acid-base analysis.
        Obstet Gynecol. 2006; 108: 1319-1322
        • James L.S.
        • Weisbrot I.M.
        • Prince C.E.
        • Holaday D.A.
        • Apgar V.
        The acid-base status of human infants in relation to birth asphyxia and the onset of respiration.
        J Pediatr. 1958; 52: 379-394
        • Perlman J.M.
        • Risser R.
        Severe fetal acidemia: neonatal neurologic features and short-term outcome.
        Pediatr Neurol. 1993; 9: 277-282
        • Luthy D.A.
        • Shy K.K.
        • Strickland D.
        • et al.
        Status of infants at birth and risk for adverse neonatal events and long-term sequelae: a study in low birth weight infants.
        Am J Obstet Gynecol. 1987; 157: 676-679
        • Westgren M.
        • Hormquist P.
        • Ingemarsson I.
        • Svenningsen N.
        Intrapartum fetal acidosis in preterm infants: fetal monitoring and long-term morbidity.
        Obstet Gynecol. 1984; 63: 355-359
        • Malin G.L.
        • Morris R.K.
        • Khan K.S.
        Strength of association between umbilical cord pH and perinatal and long term outcomes: systematic review and meta-analysis.
        BMJ. 2010; 340: c1471
        • Beeby P.J.
        • Elliott E.J.
        • Henderson-Smart D.J.
        • Rieger I.D.
        Predictive value of umbilical artery pH in preterm infants.
        Arch Dis Child Fetal Neonatal Ed. 1994; 71: F93-F96
        • Yoon B.H.
        • Romero R.
        • Yang S.H.
        • et al.
        Interleukin-6 concentrations in umbilical cord plasma are elevated in neonates with white matter lesions associated with periventricular leukomalacia.
        Am J Obstet Gynecol. 1996; 174: 1433-1440
        • Casey B.M.
        • Goldaber K.G.
        • McIntire D.D.
        • Leveno K.J.
        Outcomes among term infants when two-hour postnatal pH is compared with pH at delivery.
        Am J Obstet Gynecol. 2001; 184: 447-450
        • Ertan A.K.
        • Tanriverdi H.A.
        • Meier M.
        • Schmidt W.
        Perinatal risk factors for neonatal intracerebral hemorrhage in preterm infants.
        Eur J Obstet Gynecol Reprod Biol. 2006; 127: 29-34
        • Tejani N.
        • Verma U.L.
        Correlation of Apgar scores and umbilical artery acid-base status to mortality and morbidity in the low birth weight neonate.
        Obstet Gynecol. 1989; 73: 597-600
        • Socol M.L.
        • Garcia P.M.
        • Riter S.
        Depressed Apgar scores, acid-base status, and neurologic outcome.
        Am J Obstet Gynecol. 1994; 170: 991-998
        • Andres R.L.
        • Saade G.
        • Gilstrap L.C.
        • et al.
        Association between umbilical blood gas parameters and neonatal morbidity and death in neonates with pathologic fetal acidemia.
        Am J Obstet Gynecol. 1999; 181: 867-871
        • MacLennan A.
        A template for defining a causal relation between acute intrapartum events and cerebral palsy: international consensus statement.
        BMJ. 1999; 319: 1054-1059
        • Williams K.P.
        • Singh A.
        The correlation of seizures in newborn infants with significant acidosis at birth with umbilical artery cord gas values.
        Obstet Gynecol. 2002; 100: 557-560
        • Shah P.S.
        • McDonald S.D.
        • Barrett J.
        • et al.
        The Canadian Preterm Birth Network: a study protocol for improving outcomes for preterm infants and their families.
        CMAJ Open. 2018; 6: E44-E49
        • Lee S.K.
        • McMillan D.D.
        • Ohlsson A.
        • et al.
        Variations in practice and outcomes in the Canadian NICU network: 1996-1997.
        Pediatrics. 2000; 106: 1070-1079
        • Shah P.S.
        • Seidlitz W.
        • Chan P.
        • et al.
        Internal audit of the Canadian neonatal network data collection system.
        Am J Perinatol. 2017; 34: 1241-1249
        • Kro G.A.
        • Yli B.M.
        • Rasmussen S.
        • et al.
        A new tool for the validation of umbilical cord acid-base data.
        BJOG. 2010; 117: 1544-1552
        • Cohen A.V.
        • Schulman H.
        • Romney S.L.
        Maternal acid-base metabolism in normal human parturition.
        Am J Obstet Gynecol. 1970; 107: 933-938
        • Papile L.A.
        • Burstein J.
        • Burstein R.
        • Koffler H.
        Incidence and evolution of subependymal and intraventricular hemorrhage: a study of infants with birth weights less than 1,500 gm.
        J Pediatr. 1978; 92: 529-534
        • de Vries L.S.
        • Eken P.
        • Dubowitz L.M.
        The spectrum of leukomalacia using cranial ultrasound.
        Behav Brain Res. 1992; 49: 1-6
        • Kramer M.S.
        • Platt R.W.
        • Wen S.W.
        • et al.
        A new and improved population-based Canadian reference for birth weight for gestational age.
        Pediatrics. 2001; 108: E35
        • Baalbaki S.H.
        • Wood S.L.
        • Tita A.T.
        • Szychowski J.M.
        • Andrews W.W.
        • Subramaniam A.
        Predicting long-term neurodevelopmental outcomes in very preterm neonates by umbilical cord gas parameters.
        Am J Obstet Gynecol MFM. 2021; 3: 100248
        • Zaigham M.
        • Källén K.
        • Maršál K.
        • Olofsson P.
        Hypoxia with acidosis in extremely preterm born infants was not associated with an increased risk of death or impaired neurodevelopmental outcome at 6.5 years.
        Acta Paediatr. 2020; 109: 85-92
        • Randolph D.A.
        • Nolen T.L.
        • Ambalavanan N.
        • et al.
        Outcomes of extremely low birthweight infants with acidosis at birth.
        Arch Dis Child Fetal Neonatal Ed. 2014; 99: F263-F268
        • Tuuli M.G.
        • Stout M.J.
        • Shanks A.
        • Odibo A.O.
        • Macones G.A.
        • Cahill A.G.
        Umbilical cord arterial lactate compared with pH for predicting neonatal morbidity at term.
        Obstet Gynecol. 2014; 124: 756-761
        • Allanson E.R.
        • Waqar T.
        • White C.
        • Tunçalp Ö.
        • Dickinson J.E.
        Umbilical lactate as a measure of acidosis and predictor of neonatal risk: a systematic review.
        BJOG. 2017; 124: 584-594
        • Thorp J.A.
        • Dildy G.A.
        • Yeomans E.R.
        • Meyer B.A.
        • Parisi V.M.
        Umbilical cord blood gas analysis at delivery.
        Am J Obstet Gynecol. 1996; 175: 517-522
        • Swanson K.
        • Whelan A.R.
        • Grobman W.A.
        • Miller E.S.
        Can venous cord gas values predict fetal acidemia?.
        Am J Obstet Gynecol. 2017; 217: 364.e1-364.e5
        • Cantu J.
        • Szychowski J.M.
        • Li X.
        • et al.
        Predicting fetal acidemia using umbilical venous cord gas parameters.
        Obstet Gynecol. 2014; 124: 926-932
      1. The CRIB (clinical risk index for babies) score: a tool for assessing initial neonatal risk and comparing performance of neonatal intensive care units. The International Neonatal Network.
        Lancet. 1993; 342: 193-198
        • Beltempo M.
        • Shah P.S.
        • Ye X.Y.
        • et al.
        SNAP-II for prediction of mortality and morbidity in extremely preterm infants.
        J Matern Fetal Neonatal Med. 2019; 32: 2694-2701