Prediction of Neonatal Acidosis Based on the Type of Fetal Hypoxia Observed on the Cardiotocograph (CTG)

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  •   Shehara Amanthi Gunaratne

  •   Siromi Dilhara Panditharatne

  •   Edwin Chandraharan

Abstract

Cardiotocograph (CTG) was introduced into clinical practice to promptly recognize the features of intrapartum fetal hypoxic stress, so that timely action could be taken to avoid hypoxic-ischaemic encephalopathy (HIE) and perinatal deaths. However, the current systematic evidence suggests that the introduction of CTG into clinical practice over 50 years has not resulted in improvement in the rates of cerebral palsy or perinatal deaths. This is because most fetuses are able to withstand intrapartum hypoxic stresses without sustaining damage, and if the features of fetal compensatory responses are erroneously considered as “pathological”, “Abnormal” or “Category III” CTG tracing, it would lead to an exponential increase in unnecessary operative interventions without any improvement in perinatal outcomes. Neonatal acidosis at birth, determined by the estimation of pH in the umbilical artery has been considered as a surrogate marker of poor perinatal outcome. This is because significant intrapartum fetal hypoxic stress which leads to fetal decompensation, would lead to the onset of anaerobic metabolism and production of lactic acid in fetal tissues and organs. Entry of lactic acid into the fetal systemic circulation may cause damage to fetal central organs resulting in organ damage and death, and this lactate may lower the pH in the umbilical artery. Understanding the different types of fetal hypoxia on the CTG trace may help practicing clinicians to predict the rate of fall in fetal pH, and therefore, predict the umbilical cord pH at birth. It is important to appreciate that non-hypoxic pathways of fetal compromise such as chorioamnionitis may not be associated with low umbilical arterial pH at birth. Fetal pathophysiological approach to CTG interpretation based on deeper understanding of types of intrapartum hypoxia and features of non-hypoxic pathways of injury may help avoid the onset of neonatal metabolic acidosis and improve perinatal outcomes.


Keywords: Acute Hypoxia, Chorioamnionitis, Chronic Hypoxia, Gradually Evolving Hypoxia, Hypoxic ischaemic encephalopathy (HIE), Neonatal acidosis, Subacute Hypoxia

References

Johnson GJ, Salmanian B, Denning SG, Belfort MA, Sundgren NC, Clark SL. Relationship Between Umbilical Cord Gas Values and Neonatal Outcomes: Implications for Electronic Fetal Heart Rate Monitoring. Obstet Gynecol. 2021; 138(3): 366-373.

Yeh P, Emary K, Impey L. The relationship between umbilical cord arterial pH and serious adverse neonatal outcome: analysis of 51,519 consecutive validated samples. BJOG. 2012; 119(7): 824-31.

Intrapartum fetal heart rate monitoring: nomenclature, interpretation, and general management principles. ACOG Practice Bulletin No. 106. American College of Obstetricians and Gynecologists. Obstet Gynecol. 2009; 114: 192–202.

National Institute of Clinical Excellence. Intrapartum care: care of healthy women and their babies during labour. NICE Clinical Guideline, December 2014. [Internet] Available from: https://www.nice.org.uk/guidance/cg190/resources/intrapartum-care-for-healthy-women-and-babies-pdf-35109866447557.

Ayres-De-Campos D, Spong CY, Chandraharan E. FIGO consensus guidelines on intrapartum fetal monitoring: Cardiotocography. Int J Gynecol Obstet. 2015.

Alfirevic Z, Devane D, Gyte GM, Cuthbert A. Continuous cardiotocography (CTG as a form of electronic fetal monitoring (EFM) for fetal assessment during labour. Cochrane Database Syst Rev. 2017; 2: CD006066.

Clark SL, Hamilton EF, Garite TJ, Timmins A, Warrick PA, Smith S. The limits of electronic fetal heart rate monitoring in the prevention of neonatal metabolic acidemia. Am J Obstet Gynecol. 2017; 216(2): 163.e1-163.e6.

Chandraharan E, Evans SA, Krueger D, Pereira S, Skivens S, Zaima A. Physiological CTG interpretation. Intrapartum Fetal Monitoring Guideline. 2018. [Internet] Available from: https://physiological-ctg.com/guideline.html.

Watkins VY, Frolova AI, Stout MJ, Carter EB, Macones GA, Cahill AG, Raghuraman N. The relationship between maternal anemia and umbilical cord oxygen content at delivery. Am J Obstet Gynecol MFM. 2021; 3(1): 100270.

Chua S, Yeong SM, Razvi K, Arulkumaran S. Fetal oxygen saturation during labour. Br J Obstet Gynaecol. 1997; 104(9): 1080-3.

Pinas A, Chandraharan E. Continuous cardiotocography during labour: Analysis, classification and management. Best Pract Res Clin Obstet Gynaecol. 2016; 30: 33-47

Chandraharan E. Handbook of CTG interpretation, from patterns to physiology. First Edition, Cambridge, Cambridge University Press, 2017.

Chandraharan E and Arulkumaran S. Prevention of birth asphyxia: responding appropriately to cardiotocograph (CTG) traces. Best Pract Res Clin Obstet Gynaecol. 2007; 21: 609–624.

Galli L, Dall'Asta A, Whelehan V, Archer A, Chandraharan E. Intrapartum cardiotocography patterns observed in suspected clinical and subclinical chorioamnionitis in term fetuses. J Obstet Gynaecol Res. 2019; 45(12): 2343-2350.

Sukumaran S, Pereira V, Mallur S, Chandraharan E. Cardiotocograph (CTG) changes and maternal and neonatal outcomes in chorioamnionitis and/or funisitis confirmed on histopathology. Eur J Obstet Gynecol Reprod Biol. 2021; 260: 183-188.

Preti M, Chandraharan E. Importance of fetal heart rate cycling during the interpretation of the cardiotocograph (CTG). Int J Gynecol Reprod Sci. 2018; 1(1): 10–12.

Pereira S, Lau K, Modestini C, Wertheim D, Chandraharan E. Absence of fetal heart rate cycling on the intrapartum cardiotocograph (CTG) is associated with intrapartum pyrexia and lower Apgar scores. J Matern Fetal Neonatal Med. 2021: 1-6.

Romero R, Yoon BH, Chaemsaithong P, Cortez J, Park CW, Gonzalez R, Behnke E, Hassan SS, Chaiworapongsa T, Yeo L. Bacteria and endotoxin in meconium-stained amniotic fluid at term: could intra-amniotic infection cause meconium passage? J Matern Fetal Neonatal Med. 2014; 27(8): 775-88.

Bolten M, Chandraharan E. The Significance of ‘Non-Significant’ Meconium Stained Amniotic Fluid (MSAF): Colour versus Contents. J Adv Med Med Res. 2019.

Lee J, Romero R, Lee KA, Kim EN, Korzeniewski SJ, Chaemsaithong P, Yoon BH. Meconium aspiration syndrome: a role for fetal systemic inflammation. Am J Obstet Gynecol. 2016; 214(3): 366.e1-9.

Oikonomou M, Chandraharan E. Fetal heart rate monitoring in labor: from pattern recognition to fetal physiology. Minerva Obstet Gynecol. 2021; 73(1): 19-33.

Jia YJ, Chen X, Cui HY, Whelehan V, Archer A, Chandrahan E. Physiological CTG interpretation: the significance of baseline fetal heart rate changes after the onset of decelerations and associated perinatal outcomes. The Journal of Maternal-Fetal & Neonatal Medicine. 2021; 34(14): 2349-2354.

Gracia-Perez-Bonfils A, Vigneswaran K, Cuadras D, Chandraharan E. Does the saltatory pattern on cardiotocograph (CTG) trace really exist? The ZigZag pattern as an alternative definition and its correlation with perinatal outcomes. J Matern Fetal Neonatal Med. 2019: 1-9.

Leung TY, Chung PW, Rogers MS, Sahota DS, Lao TT, Hung Chung TK. Urgent cesarean delivery for fetal bradycardia. Obstet Gynecol. 2009; 114(5): 1023-1028

Lepercq J, Nghiem MA, Goffinet F. Fetal heart rate nadir during bradycardia and umbilical artery acidemia at birth. Acta Obstet Gynecol Scand. 2021; 100(5): 964-970.

Pereira S, Chandraharan E. Recognition of chronic hypoxia and pre-existing foetal injury on the cardiotocograph (CTG): Urgent need to think beyond the guidelines. Porto Biomed J. 2017; 2(4): 124-129.

McDonnell S, Chandraharan E. The Pathophysiology of CTGs and Types of Intrapartum Hypoxia. Current Women`s Health Reviews. 2013; 9(3).

Yanamandra N, Chandraharan E. Saltatory and sinusoidal fetal heart rate (FHR) patterns and significance of FHR ‘overshoots’. Curr Wom Health Rev. 2013; 9: 1e8.

Yatham SS, Whelehan V, Archer A, Chandraharan E. Types of intrapartum hypoxia on the cardiotocograph (CTG): do they have any relationship with the type of brain injury in the MRI scan in term babies? J Obstet Gynaecol. 2020; 40(5): 688-693.

Pereira S, Patel R, Zaima A, Tvarozkova K, Chisholm P, Kappelou O, Evanson J, Chandraharan E, Wertheim D, Shah DK. Physiological CTG categorization in types of hypoxia compared with MRI and neurodevelopmental outcome in infants with HIE. J Matern Fetal Neonatal Med. 2022: 1-9.

Samyraju M, Ledger S, Chandraharan E. Introduction of the Physiological CTG Interpretation & Hypoxia in Labour (HIL) Tool, and its Incorporation into a Software Programme: Impact on Perinatal Outcomes. Glob J Reprod Med. 2021; 8(3): 5556737.

Chandraharan E, Lowe V, Ugwumadu A, Arulkumaran S (2013) Impact of Fetal ECG (STA N) and competency-based training on intrapartum interventions and perinatal outcomes at a Teaching Hospital in London: 5 Year Analysis. BJOG. 120: 428-429.

Ingram C, Gupta N, Mustafa S, Singh M, Chandraharan E. Impact of Physiological CTG Guidelines on Intrapartum Hypoxic injuries and brain cooling. World Congress of the Royal College of Obstetricians and Gynaecologists (RCOG) 2021.

Reeves K, Scully R, Dutta A, Bullen-Bull R, Singh M, Chandraharan E. Training and support on Physiological CTG Interpretation : Does it reduce the hypoxic encephalopathy (HIE) rate? European Congress on Intrapartum Care. 2021.

Chandraharan E, Tahan ME, Pereira S. Each Fetus Matters: An Urgent Paradigm Shift is needed to Move away from the Rigid "CTG Guideline Stickers" so as to Individualize Intrapartum Fetal Heart Rate Monitoring and to improve Perinatal Outcomes. Obstet Gynecol Int J. 2016; 5(4): 00168.

Chandraharan E. Intrapartum care: An urgent need to question historical practices and ‘non-evidence’-based, illogical foetal monitoring guidelines to avoid patient harm. Journal of Patient Safety and Risk Management. 2015; 24(5): 210-217.Chandraharan E, Arulkumaran S. Acute tocolysis. Curr Opin Obstet Gynecol. 2005; 17(2): 151-6.

Sherman DJ, Frenkel E, Kurzweil Y, Padua A, Arieli S, Bahar M. Characteristics of maternal heart rate patterns during labor and delivery. Obstet Gynecol. 2002; 99(4): 542-7.

Nurani R, Chandraharan E, Lowe V, Ugwumadu A, Arulkumaran S. Misidentification of maternal heart rate as fetal on cardiotocography during the second stage of labor: the role of the fetal electrocardiograph. Acta Obstet Gynecol Scand. 2012; 91(12): 1428-32.

Saeed F, Abeysuriya S, Chandraharan E. Erroneous Recording of Maternal Heart Rate as Fetal Heart Rate During Second Stage of Labour: Isn’t it Time to Stop this? J Biomed Res Environ Sci. 2021; 2(5): 315-319.

Al Fahdi B, Chandraharan E. True vs Spurious Intrapartum Fetal Heart Rate Accelerations on the Cardiotocograph (CTG): An Urgent Need for Caution. Glob J Reprod Med. 2020; 7 (5): 5556722.

Chandraharan E, Arulkumaran S. Medico-legal problems in obstetrics. Current Obstetrics & Gynaecology. 2006; 16: 206-210.

Malin GL, Morris RK, Khan KS. Strength of association between umbilical cord pH and perinatal and long term outcomes: systematic review and meta-analysis. BMJ. 2010; 340: c1471.

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How to Cite
Gunaratne, S. A., Panditharatne, S. D., & Chandraharan, E. (2022). Prediction of Neonatal Acidosis Based on the Type of Fetal Hypoxia Observed on the Cardiotocograph (CTG). European Journal of Medical and Health Sciences, 4(2), 8–18. https://doi.org/10.24018/ejmed.2022.4.2.1308