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South Australian Perinatal Practice Guideline 

Fetal Acid Base Balance 
Assessment  

  Department for Health and Wellbeing, Government of South Australia. All rights reserved. 

 

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Note:

This guideline provides advice of a general nature.  This statewide guideline has been prepared to promote and facilitate 
standardisation and consistency of practice, using a multidisciplinary approach.  The guideline is based on a review of 
published evidence and expert opinion.  

Information in this statewide guideline is current at the time of publication.  

SA Health does not accept responsibility for the quality or accuracy of material on websites linked from this site and does not 
sponsor, approve or endorse materials on such links. 

Health practitioners in the South Australian public health sector are expected to review specific details of each patient and 
professionally assess the applicability of the relevant guideline to that clinical situation. 

If for good clinical reasons, a decision is made to depart from the guideline, the responsible clinician must document in the 
patient s medical record, the decision made, by whom, and detailed reasons for the departure from the guideline. 

This statewide guideline does not address all the elements of clinical practice and assumes that the individual clinicians are 
responsible for discussing care with consumers in an environment that is culturally appropriate and which enables respectful 
confidential discussion. This includes: 

  The use of interpreter services where necessary, 
  Advising consumers of their choice and ensuring informed consent is obtained, 
  Providing care within scope of practice, meeting all legislative requirements and maintaining standards of 

professional conduct, and  
  Documenting all care in accordance with mandatory and local requirements 

 

 
Explanation of the aboriginal artwork: 
The Aboriginal artwork used symbolises the connection to country and the circle shape shows the strong relationships amongst families and the Aboriginal culture. The horse shoe shape 
design shown in front of the generic statement symbolises a woman and those enclosing a smaller horse shoe shape depicts a pregnant woman. The smaller horse shoe shape in this 
instance represents the unborn child. The artwork shown before the specific statements within the document symbolises a footprint and demonstrates the need to move forward together in 
unison. 

 

     

 

 

 

 

 
 

Purpose and Scope of Perinatal Practice Guideline (PPG) 

The purpose of this guideline is to give information about monitoring of fetal wellbeing in 
labour. It describes indications and contraindications for fetal scalp blood sampling as well as 
how to undertake the procedure. Similarly, information is provided about cord blood gas 
sampling as the best determinant of fetal metabolic condition at the moment of birth. 

Australian Aboriginal Culture is the oldest living culture in the world yet 

Aboriginal people continue to experience the poorest health outcomes when 

compared to non-Aboriginal Australians. In South Australia, Aboriginal women are 

2-5 times more likely to die in childbirth and their babies are 2-3 times more likely to 

be of low birth weight.  The accumulative effects of stress, low socio economic 

status, exposure to violence, historical trauma, culturally unsafe and discriminatory 

health services and health systems are all major contributors to the disparities in 

Aboriginal maternal and birthing outcomes. Despite these unacceptable statistics 

the birth of an Aboriginal baby is a celebration of life and an important cultural 

event bringing family together in celebration, obligation and responsibility. The 

diversity between Aboriginal cultures, language and practices differ greatly and so 

it is imperative that perinatal services prepare to respectfully manage Aboriginal 

protocol and provide a culturally positive health care experience for Aboriginal 

people to ensure the best maternal, neonatal and child health outcomes. 

 



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Flowchart: Fetal Scalp Blood Sampling 

 

  



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Table of contents 
Purpose and Scope of Perinatal Practice Guideline (PPG) ...................................................... 1 

Flowchart: Fetal Scalp Blood Sampling ..................................................................................... 2 

Summary of Practice Recommendations .................................................................................. 3 

Abbreviations ............................................................................................................................. 4 

Introduction ................................................................................................................................ 4 

Tests to monitor fetal wellbeing in labour .................................................................................. 4 

Fetal scalp stimulation ........................................................................................................... 4 

Fetal electrocardiograph (ECG) ST analysis ......................................................................... 5 

Fetal pulse oximetry ............................................................................................................... 5 

Fetal scalp blood sampling ........................................................................................................ 5 

Fetal scalp lactate and pH levels ........................................................................................... 6 

Indications for fetal scalp blood sampling .............................................................................. 6 

Contraindications to fetal scalp blood sampling .................................................................... 6 

Management of fetal scalp blood sampling ........................................................................... 6 

Procedure for fetal scalp blood sampling .............................................................................. 7 

Results ................................................................................................................................... 8 

Cord blood gases ....................................................................................................................... 9 

Indications .............................................................................................................................. 9 

Considerations ....................................................................................................................... 9 

Technique for obtaining umbilical cord blood gases ............................................................ 10 

References ............................................................................................................................... 11 

Acknowledgements .................................................................................................................. 12 

Document Ownership &amp; History ............................................................................................... 13 

 

 

Summary of Practice Recommendations  

In tertiary centres, fetal scalp blood sampling (FBS) should be considered part of routine care 
for the management team when indicated. 

Interpretation of FBS results should take into account any previous scalp pH or lactate results, 
labour progress and the complete clinical picture.  

FBS should not be undertaken in the presence of maternal infection, fetal bleeding disorders, 
malpresentation (e.g. breech, brow, face) or when there is clear evidence of sustained serious 
fetal compromise on CTG. 

FBS is not recommended in pregnancies less than 35 weeks  gestation. 

Scalp lactate rather than pH measurement may be easier to perform and more affordable. 

Undertaking FBS may unnecessarily increase the decision to birth interval when expediting 
birth is indicated (e.g. evidence of serious fetal compromise). 

Paired umbilical arterial and venous cord blood gases should be taken whenever fetal 
compromise is suspected (see Indications). 

Once available, abnormal cord blood gas results should be discussed with the neonatal/ 
paediatric team.  



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Abbreviations   

CTG Cardiotocography 

FHR Fetal Heart Rate 

ECG Electrocardiography 

cm Centimetres 

RANZCOG Royal Australian and New Zealand College of Obstetricians and 
Gynaecologists 

HIV Human Immunodeficiency virus  

mL Millimetre(s)  

e.g. For example 

% Percentage 

RCOG Royal College of Obstetricians and Gynaecologists 

i.e. That is 

C Celsius 

g Gauge 

mmol/L Millimols per litre 

pCO2  Partial pressure of Carbon Dioxide 

FBS Fetal Blood Sampling 

 

Introduction 

Intrapartum fetal surveillance frequently involves the use of a cardiotocograph (CTG).1 The 
CTG is an electronic method of simultaneously recording the fetal heart rate (FHR), fetal 
movements and uterine contractions to identify the probability of fetal hypoxia. In nearly half 
of all CTG tracings, an abnormal fetal heart rate is observed, but only a small proportion of 
these fetuses are actually hypoxic.2 Cardiotocography has a high degree of sensitivity but a 
low level of specificity.3 Fetal blood sampling is usually performed to better assess fetal acid-
base status in the setting of an abnormal CTG.3 

Tests to monitor fetal wellbeing in labour 

Several ancillary tests to continuous fetal heart rate monitoring have been proposed to 
decrease the false positive rate, or even to replace it completely.  These include: 

? Fetal scalp blood sampling*   

? Fetal scalp stimulation 

? Fetal ECG ST analysis 

? Fetal oximetry   

The gaps in understanding of the precise pathophysiology of the development of 
metabolic acidosis during labour hinders the efficacy of ALL of the above fetal tests.4  

*Fetal scalp blood sampling will be discussed in detail below 

Fetal scalp stimulation 

Fetal scalp stimulation during vaginal examination is a non-invasive assessment of the fetus 
that may provide assurance alongside continuous fetal heart rate monitoring and fetal scalp 
blood sampling in cases of suspected fetal compromise.  The likelihood ratio of an 
acceleration following fetal scalp stimulation for having low scalp pH is 0.5.7 If fetal scalp 
stimulation leads to an acceleration in the fetal heart rate, clinicians can regard this as a 
reassuring feature and take this into account whilst reviewing the whole clinical picture.5 

  



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Fetal electrocardiograph (ECG) ST analysis 

Meta-analysis of randomised controlled trials has shown fetal ECG ST analysis reduces the 
need for fetal scalp blood sampling by about 40%.  However, the trends to lower rates of low 
Apgar scores and acidosis were not statistically significant.6 ST analysis of the fetal ECG in 
labour reduces the need for fetal blood sampling but has no other statistically significant 
benefit and does not reduce the caesarean section rate.6 

Currently, RANZCOG states there is insufficient evidence to recommend routine fetal ECG 
ST analysis for use in intrapartum fetal surveillance.1 

Fetal pulse oximetry 

Currently, RANZCOG states there is insufficient evidence to recommend routine fetal pulse 
oximetry for use in intrapartum fetal surveillance.1  

Fetal pulse oximetry results are affected by the presence of meconium and blood and a 
recent Cochrane review has concluded that fetal pulse oximetry is not associated with 
improvement in fetal outcomes.7 

Fetal scalp blood sampling 

A recent systematic review of intermittent auscultation versus continuous CTG in both low 
and high risk women reveals a significant increase in the caesarean section rate in the CTG 
group, whether fetal blood sampling was deployed in labour or not.1,8  It is therefore possible 
that the availability of fetal blood sampling in labour will lessen the increase in the caesarean 
rate that comes as a consequence of using continuous CTG.8 

Although fetal scalp blood sampling is generally considered to be a safe test, rare 
complications (e.g. haemorrhage, scalp abscess and drainage of cerebrospinal fluid) and 
questions regarding the accuracy of current, normal and abnormal values for fetal scalp pH 
(derived from two small studies) as well as the accuracy of pH levels obtained from a fetal 
scalp venous sample have led some medical experts to question if this procedure is clinically 
and scientifically acceptable.4,8 

RANZCOG supports the practice of fetal scalp blood sampling, particularly in larger units that 
have ready access to operative delivery if required.1 However, RANZCOG acknowledge that 
it is not practical for ALL Australian and New Zealand hospitals to provide fetal blood 
sampling. For example, in some hospitals, undertaking fetal blood sampling may delay a 
necessary birth and thereby worsen outcomes by lengthening the decision to birth interval for 
an emergency caesarean section.1  

? In the past, some hospitals interested in providing fetal blood sampling were unable 
to because of the costs of maintaining the necessary hardware. More recently, the 
introduction and validation of scalp lactate measurement has provided an affordable 
alternative.1 If fetal scalp blood sampling is indicated, the use of scalp lactate rather 
than pH measurement will provide an easier and more affordable adjunct to electronic 
fetal heart rate monitoring for most units.1,9  

? If fetal scalp blood sampling is performed, the scalp lactate or pH result should be 
interpreted taking into account any previous lactate or pH measurement, the rate of 
progress in labour and the clinical features of the woman and baby.1,5  

? Inform the senior consultant obstetrician on call if any fetal scalp blood sample result 
is abnormal 
 

In situations where fetal blood sampling is contraindicated (see below) or not possible, 
decisions regarding birth should take into account the severity of the fetal heart rate 
abnormality and the clinical situation. Birth should be expedited where: 

? There is clear evidence of serious fetal compromise (fetal scalp blood sampling 
should not be undertaken)1 

? CTG abnormalities are of a degree requiring further assessment, but fetal scalp blood 
sampling is contraindicated, clinically inappropriate or unobtainable1 

? The decision to birth interval may be prolonged by virtue of location, clinical staff 
availability, patient factors or access to clinical services1 



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Fetal scalp lactate and pH levels 

A randomised, controlled multicentre trial showed pH analysis and lactate analysis of fetal 
blood have comparable results in the management of intrapartum fetal compromise.2 If fetal 
blood sampling is indicated, the use of scalp lactate rather than pH measurement is easier to 
perform for clinicians, is more affordable and requires a smaller volume of blood.1 

Indications for fetal scalp blood sampling 

Factors including clinical history, parity, evolution of the fetal heart rate pattern, stage and rate 
of progress in labour influence the decision for fetal scalp blood sampling.  

Fetal scalp blood estimation may be of value in the following circumstances:  

? Bradycardia 

? Complicated tachycardia 

? Recurrent decelerations 

? Prolonged episodes of bradycardia or undefined deceleration patterns 

? Prolonged loss of variability which does not spontaneously correct with fetal 
stimulation 

? Miscellaneous e.g. non-specific concerns about fetal wellbeing 

Contraindications to fetal scalp blood sampling 

? Clear evidence on CTG of serious, sustained fetal compromise 

? Maternal infection e.g. Hepatitis B, C, HIV, herpes simplex virus and suspected 
intrauterine sepsis 

? Fetal bleeding disorders (e.g. suspected fetal thrombocytopenia, haemophilia)  

? Face or brow presentation 

? Fetal blood sampling is not generally recommended in pregnancies at less than 34+6 
weeks of gestation because birth may be inappropriately delayed in a small  at risk  
fetus that may sustain damage earlier than would be expected in a term fetus 1  

? If a fetus is in a breech presentation during labour and is exhibiting signs of fetal 
compromise that are not readily remediable, it would be more appropriate to deliver 
the baby by caesarean section than to undertake fetal blood sampling1 

Management of fetal scalp blood sampling 

In tertiary centres, fetal scalp blood sampling should be considered part of routine care for the 
management team when indicated, and a competency the resident medical officer or registrar 
should be able to fulfil. Ensure the blood gas analyser has been calibrated according to local 
hospital guidelines prior to the processing of samples. 

Explain the following to the woman:5  

? Why the test is being advised 

? The blood sample will be used to measure the level of acid in the baby's blood, to see 
how well the baby is coping with labour 

? The procedure will require her to have a vaginal examination using a small device 
similar to a speculum  

? A sample of blood will be taken from the baby's head by making a small scratch on 
the baby's scalp. This will heal quickly after birth, but there is a small risk of infection 

? The procedure can help to reduce the need for further, more serious interventions 

? What the different outcomes of the test may be (normal, borderline and abnormal) 
and the actions that will follow each result 

? There is a small chance that it will not be possible to obtain a blood sample 
(especially if the cervix is less than 4 cm dilated). If a sample cannot be obtained, a 
caesarean section or instrumental birth (forceps or ventouse) may be needed 
because otherwise it is not possible to find out how well the baby is tolerating labour 

  



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Procedure for fetal scalp blood sampling 

Position: 

The preferred maternal position is left-lateral position with hips well flexed and the lower leg 
extended. The upper leg should be flexed (held by an assistant or positioned in a stirrup) with 
the buttocks extending over the edge of the bed to allow the clinician to be positioned below 
the level of the maternal vagina. If lithotomy position is used, ensure a lateral wedge is used 
to prevent aortocaval compression. 

Procedure: 

? Disposable fetal scalp blood sampling kits should be available for clinician use 

? Attach the fetal scalp blade (depth of 2 mm) to an introducer  

? Under direct vision, insert the amnioscope with light source into the posterior fornix  

? The clinician obtaining the scalp sample should aim to angle the amnioscope 
downward below the horizontal plane 

? Once past the anterior lip of the cervix, angle the cone anteriorly into the cervix to 
visualise the presenting part 

? Clean the fetal scalp surface with chlorhexidine / alcohol-soaked gauze 

? Apply sterile liquid paraffin to the fetal scalp (forms a non-wettable surface and 
encourages beading of fetal scalp blood)  

? Make a quick stab with the fetal scalp blade / introducer to achieve a clean incision on 
the fetal scalp  

? As the fetal blood appears, insert the heparinised capillary tube to touch the drop of 
blood, and keeping the tube angled downward, the blood is allowed to flow by gravity 

o FBS for pH: Let the tube fill with at least 2 cm of blood (without air bubbles or 
liquor) 

o FBS for lactate:  A minimum of 5 microlitres of blood is required (without air 
bubbles or liquor) 

? Immediately pass the sample to an assistant for processing 

? Obtain two samples  

? Apply pressure with a swab to the fetal scalp over the next two contractions and 
observe to ensure the bleeding has stopped  

  



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Results  

The following thresholds are suggested and clinicians should be aware that thresholds 
may vary between institutions: 

 

Fetal scalp blood sampling  

Lactate and pH result Management 

Lactate &lt; 4.1 mmol/L 
Fetal scalp blood sample is normal  

Offer repeat sampling no more than 1 hour later if this is 
still indicated by the CTG trace, or sooner if additional 
signs of fetal compromise or abnormal features become 
evident5  

pH ? 7.25 

Lactate 4.1- 4.7 mmol / L 
Fetal blood sample result is borderline 

Offer repeat sampling no more than 30 minutes later if 
this is still indicated by the  CTG trace, or sooner if 
additional signs of fetal compromise or abnormal features 
become evident5  

Take into account the time needed to take a fetal blood 
sample when planning repeat fetal sampling5 

Note: Notify obstetrician on call to consider further 

management/mode of birth if rapid fall since last sample  

pH 7.21   7.24 

Second fetal scalp blood 

sample result is stable and  
no further signs of fetal 
compromise 

If the CTG trace remains unchanged and the fetal scalp 
blood sample result is stable (that is lactate or pH is 
unchanged) after a second test, further samples may be 
deferred unless additional  signs of fetal compromise or 
abnormal features are seen 5 

Lactate &gt; 4.7 mmol / L 
Birth indicated  

Rapid deterioration in features of fetal compromise 
requires obstetric review of timing and mode of birth  

Consider the woman s complete history (e.g. presence of 
meconium, progress, fetal scalp lactate or pH value) 
when assessing need for caesarean section (category 1) 

pH ? 7.20: 

Lactate of ? 5.8 mmol / L 
Requires an urgent assisted vaginal birth if possible or a 
category 1 caesarean section  

 pH &lt; 7.00 

 
Discuss with the senior obstetrician if: 

? A fetal blood sample cannot be obtained, OR 

? A third fetal blood sample is thought to be needed 

 

Fetal scalp blood sample cannot be obtained 

If a fetal scalp blood sample is indicated and the sample cannot be obtained, but the 
associated scalp stimulation results in fetal heart rate accelerations, a decision whether to 
continue the labour or expedite the birth will be made in consideration of the clinical 
circumstances and in discussion with the consultant obstetrician on call and the woman.5 

If a fetal scalp blood sample is indicated but a sample cannot be obtained and there is no 
improvement in the CTG trace, advise the woman that the birth should be expedited.3 

? Notify the anaesthetist and paediatrician 

? Urgency of birth should take into account the severity of fetal compromise and 
relevant maternal factors  

  



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No sample or one contaminated with liquor or inadequate volume sample obtained: 

Review indication for fetal scalp blood sampling and current CTG trace. Consider the need for 
birth in consultation with the senior obstetrician on call. 

Cord blood gases  

Fetal arterial and venous cord gases (pH, base excess and lactate) are not required for 
uncomplicated term spontaneous vaginal births.   

Even when paired samples are obtained it cannot always be assumed that one is from an 
artery and one from the vein. Fetal carbon dioxide is removed from the umbilical arterial blood 
in the placenta, umbilical venous blood should have a slightly higher pH and lower pCO2 than 
umbilical arterial blood.12  

Umbilical cord blood gas sampling is the most objective determinant of fetal metabolic 
condition at the moment of birth.13  

Values from the umbilical cord artery provide the most accurate information regarding fetal 
and newborn acid-base status.13 Information gained from umbilical cord blood sampling can 
be useful from a medical and medicolegal perspective.14 

A cord base excess of 12 to 16 mmol/L is associated with encephalopathy in 10 % of 
neonates, and the rate increases to 40 % in neonates who have an umbilical arterial base 
deficit greater than 16 mmol/L.13  

Indications 

Where facilities are available, paired umbilical arterial and venous cord blood gas samples 
(pH, base excess and lactate) should be taken after birth in the following situations1, 13, 14: 

? When the clinicians are concerned about a potential fetal metabolic abnormality 

? Preterm gestation 

? Meconium stained liquor 

? Assisted emergency birth (i.e. ventouse, instrumental, emergency caesarean section) 

? Vaginal breech birth 

? Shoulder dystocia 

? Intrapartum fever (? 38 C) 

? Maternal thyroid disease 

? Multiple pregnancy 

? Small for gestational age baby 

? Intrapartum haemorrhage 

? Intrapartum fetal scalp pH performed  

? Any significant intrapartum CTG abnormality  

? Apgar ? 4 at 1 minute 

? Apgar ? 7 at 5 minutes 

? Planned neonatal nursery admission 

Considerations 

It is imperative to clamp the cord as soon as possible after the birth because a delay in 
clamping may significantly affect pH and gas values due to gaseous diffusion and continuing 
metabolism.14 However, clinicians should be aware of maternal requests regarding delayed 
cord clamping and the individual clinical scenarios. 

Most studies have determined that a cord blood sample is stable for assessment of both pH 
and base deficit for 60 minutes when collected in a syringe flushed with heparin and 
transported to the cord blood gas analysis machine on ice.14 

Arterial pH, base excess and lactate at birth can be estimated from testing a blood sample 
obtained from a clamped umbilical cord kept at room temperature for up to 90 minutes after 
birth.14 

If obtaining umbilical cord artery blood samples is difficult, the vessels on the fetal surface of 
the placenta can be used (arteries cross over veins) and will provide similar, but not 
necessarily equivalent results.14 



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If the baby is born in poor condition (the Apgar score at 1 minute is 5 or less), a 10-20cm 
segment of umbilical cord is doubly clamped as soon as possible after birth to allow paired 
cord blood gases to be taken.14   

It is important to label the samples as either arterial or venous. 

Where paired umbilical cord blood gas analysis is taken at birth as part of a clinical audit 
regimen, this process should not interfere with management of the third stage of labour.1 

Ensure the time that the cord was clamped post birth is recorded in the baby s case notes. 

Technique for obtaining umbilical cord blood gases 

If acid-base analysis is planned, the cord should be clamped as soon as possible following 
the birth of the baby. 

Technique One 

1. A 10-20cm segment of umbilical cord is doubly clamped as soon as possible after 
birth and prior to the delivery of the placenta 

2. Collect cord blood gases from the cord vessels above the bottom clamp prior to 
collecting routine cord blood samples 

Technique Two 

1. A 10-20cm section of umbilical cord can be double clamped prior to the delivery of 
the placenta. A third clamp can be placed above the isolated section. The isolated 
section can be detached and set aside in order to take arterial and venous paired 
samples  

2. Cord blood gases can then be collected from the detached cord section. After the 
birth of the baby, clamp and cut the umbilical cord to separate the baby from the 
placenta as in normal vaginal birth. If the Apgar is less than 5 at one minute, clamp 
and cut the cord immediately  

 

For all collections 

? Use heparinised blood gas syringes (pre-packed if available) or attach a 21 g (green) 
needle to each heparinised blood gas syringe  

? Identify one artery and vein separately 

? Collect the arterial sample first  

? Clean the segment of the cord that the sample will be collected from with a clean 
perineal pad to remove maternal blood or contaminants 

? Insert the needle parallel to the vessel (less likely to go through the back of the artery 
into the vein) and withdraw a minimum of 0.2 mL from the artery  

? Remove the needle with caution as blood may spray up from the puncture site, 
discard into the sharps receptacle, expel air from the syringe and cap with the stopper 
provided 

? Invert tube to mix specimen and hand the specimen to the assistant to label 
appropriately with unique neonatal identification labels, date and time of collection 
and whether the source of the sample is arterial or venous 

? Then collect the venous blood gas specimen in the same way 

 

Facilitate timely analysis and reporting of cord blood gases per individual hospital policy 
Suggested levels for reporting to neonatologists include (if local hospital polices are not in 
place): 

? pH &lt; 7.15 

? Base Excess &gt; -10 

? Lactate &gt; 5 

? Haemoglobin &lt; 140 

? Glucose &lt; 3 

Once available, abnormal results should be discussed with the neonatal team and 
documented in the baby s case notes, including the agreed plan. Normal results should also 
be documented in the case notes.  

  



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References 

1. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists. 
Intrapartum Fetal Surveillance Clinical Guideline 3rd Ed. 2014. 

2. Wiberg-Itzel E, Lipponer C, Norman M, et al. Determination of pH or lactate in fetal 
scalp blood in management of intrapartum fetal distress: randomised controlled 
multicentre trial. BMJ 2008; 336(7656): 1284. 

3. Baker L, Beaves M, Wallace E. Assessing Fetal Wellbeing a Practical Guide. 
Melbourne, Victoria: RANZCOG &amp; Monash Health; 2016. 

4. Chandraharan E. Fetal scalp blood sampling during labour: is it a useful diagnostic 
test or a historical test that no longer has a place in modern clinical obstetrics? BJOG: 
An International Journal of Obstetrics &amp; Gynaecology. 2014; 121(9): 1056-62. 

5. National Institute for Health and Care Excellence (NICE). Intrapartum care for healthy 
women and babies - Clinical Guideline. 2014, Dec 3. UK: NICE; 2014. Available from: 
https://www.nice.org.uk/guidance/cg190. 

6. Steer PJ, Hvidman LE. Scientific and clinical evidence for the use of fetal ECG ST 
segment analysis (STAN). Acta Obstetricia et Gynecologica Scandinavica 2014; 
93(6): 533-8. 

7. East C, Begg L, Colditz P, Lau R. Fetal pulse oximetry for fetal assessment in labour.  
Cochrane Database of Systematic Reviews; 2014. Issue 10. Art. No.: CD004075. 

1. DOI: 10.1002/14651858.CD004075.pub4 Available from: 
http://www.cochrane.org/CD004075/PREG_fetal-pulse-oximetry-for-fetal-
assessment-in-labour.  

8. Alfirevic Z, Devane D, Gyte GML. Continuous cardiotocography (CTG) as a form of 
electronic fetal monitoring (EFM) for fetal assessment during labour. Cochrane 
Database of Systematic Reviews; 2013. Issue 5. Art. No.: CD006066.DOI: 
10.1002/14651858.CD006066.pub2. Available from: 
http://dx.doi.org/10.1002/14651858.CD006066.pub2.   

9. East C, Leader L, Sheehan P, Henshall N, Colditz P, Lau R. Intrapartum fetal scalp 
lactate sampling for fetal assessment in the presence of a non-reassuring fetal heart 
rate trace.  Cochrane Database of Systematic Reviews; 2015. Issue 5. Art. No.: 
CD006174.DOI: 10.1002/14651858.CD006174.pub3. Available from: 
http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD006174.pub3/full.  

10. Andres RL, Saade G, Gilstrap LC, et al. Association between umbilical blood gas 
parameters and neonatal morbidity and death in neonates with pathologic fetal 
acidemia. American Journal of Obstetrics and Gynecology. 1999; 181(4): 867-71. 

11. Freeman R, Garite T, MP N. Fetal Heart Rate Monitoring. 3rd ed. Philadelphia: 
Lippincott Williams &amp; Wilkins; 2003. 

12. Armstrong L, Stenson BJ. Use of umbilical cord blood gas analysis in the assessment 
of the newborn. Archives of Disease in Childhood - Fetal and Neonatal Edition 2007; 
92(6): F430. 

13. The American College of Obstetricians and Gynaecologists (ACOG). Umbilical cord 
blood gas and acid-base analysis ACOG. Committee Opinion No. 348, November 
2006: 108(5): 1319-22. 

14. Ramin S. Umbilical cord blood acid-base analysis at delivery. In: Lockwood C, Ed. 
2016 Oct 6 [cited 2017 Jan 2]. Available from: https://www.uptodate.com. 

 

 

 

 

  



South Australian Perinatal Practice Guideline 

Fetal Acid Base Balance Assessment 
 

 

 
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Acknowledgements 

The South Australian Perinatal Practice Guidelines gratefully acknowledge the contribution of 
clinicians and other stakeholders who participated throughout the guideline development 
process particularly:  

Write Group Lead 

Dr Angela Brown 

Write Group Members 

Lyn Bastian 
Dr Aishah Yasin 
A/Prof Rosalie Grivell 
Rachael Yates 
Dr Sameer Dikshit 

SAPPG Management Group Members 

Sonia Angus 
Lyn Bastian 
Dr Elizabeth Beare 
Elizabeth Bennett 
Dr Feisal Chenia 
John Coomblas 
Dr Danielle Crosby 
Dr Vanessa Ellison 
Jackie Kitschke 
Dr Kritesh Kumar 
Catherine Leggett 
Dr Anupam Parange 
Rebecca Smith 
A/Prof Chris Wilkinson 

  



South Australian Perinatal Practice Guideline 

Fetal Acid Base Balance Assessment 
 

 

 
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Document Ownership &amp; History 

Developed by: SA Maternal, Neonatal &amp; Gynaecology Community of Practice 
Contact: HealthCYWHSPerinatalProtocol@sa.gov.au 
Endorsed by: SA Health Safety and Quality Strategic Governance Committee 
Next review due:  14/11/2022     
ISBN number:  978-1-74243-935-8 
PDS reference:  CG233 
Policy history: Is this a new policy (V1)?  N 
 Does this policy amend or update and existing policy?  Y 

 If so, which version? V5 
 Does this policy replace another policy with a different title? N 
 If so, which policy (title)? 
 
 

Approval 
Date 

Version 
Who approved New/Revised 
Version 

Reason for Change 

25/11/20 V5.1 
Interim Chair, SA Maternal, Neonatal &amp; 
Gynaecology Community of Practice 

Re-templated, risk assessed and 
extended for 2 years 

14/11/17  V5 
SA Health Safety and Quality Strategic 
Governance Committee 

Reviewed and merged with Umbilical 
Cord Blood Gas Sampling PPG 

19/04/16  V4 
SA Health Safety and Quality Strategic 
Governance Committee 

Reviewed 

22/11/11  V3 
SA Health Maternal and Neonatal 
Network 

Reviewed 

23/10/07  V2 
SA Health Maternal and Neonatal 
Network 

Reviewed 

18/03/04  V1 
SA Health Maternal and Neonatal 
Network 

Original SA Health Maternal and 
Neonatal Network approved version. 

 



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