Interpretation
Overall EA use in vaginal birth in Austria was increasing over the last
ten years, but still differ from other European countries with
comparable health care
systems.11,17,18The pH of umbilical arterial cord blood is a practical measure for
evaluating foetal acidosis and is routinely measured with blood gas
analysis.19Our findings were comparable to a single and a multicentre study,
showing no relation of EA on neonatal morbidity, defined as
pH<7.1, APGAR score after 5 minutes <7, neonatal
resuscitation, or composite
morbidity.20,21Anim-Somuah and colleagues could not demonstrate a significant
difference in the frequency of acidosis, defined as pH<7.2 or
7.15 in a 2018 published Cochrane review comparing opioid administration
or other non-epidural pain therapies and
EA.3BE reflects metabolic acid-base abnormalities. The potentially
beneficial effects of EA on BE may be explained by increased uterine
blood flow after EA when hypotension is prevented, however observed
effect estimates appear clinically not relevant. In a 2002 published
meta-analysis of studies comparing EA with systemic analgesics, BE was
less negative in the EA groups in randomised as well as observational
studies.22
Even though AS5<7 was only present in 0.7% of neonates, it
was significantly more often observed in the EA group (adjusted OR
1.18). A Swedish population-based study based on data from 1999-2008
demonstrated an adjusted OR of 1.27 for AS5<7 with EA, with
quite similar rates (0.8% vs.
1.3%),11while in more recent trials, AS5<7 was not related to EA
use.3,20When low concentrations of local anesthetics for EA were used in
nulliparous women, AS5<7 was observed with an incidence of
0.15% and showed no significant difference to non-epidural opioid pain
relief in a meta-analysis published by Liu et al. in
2004.23Short-term morbidity may be higher when prolonged duration of birth was
present and instrumental delivery was applied, which could be the case
when higher doses of local anesthetics potentially led to motor
blockade. Both of these circumstances were present in the examined EA
group without clear association to EA itself. This assumption is
supported by a recently published survey, asking for current obstetric
anaesthesia practice in Austria, in which 51% reported to use
ropivacaine 0.2%, while only up to 11% using potent epidural opioid
adjuncts to reduce local anaesthetic dose. Further, the survey revealed,
that only 42% of respondents generally perform EA independently of
cervical dilatation, making it more likely that the indication for EA
was an already prolonged or unusually painful birth
period.14 So, EA may be used more extensively in
already complicated and complex or induced deliveries, in request for
relief of emerging pain. This in mind, our data analysis was not
adjusted for cases of EA, in which parturients received EA in a very
late phase of delivery, probably not affecting birth progression at all,
or were even given due to complications in progress of labour.
The association of admission to NICU with EA, even after correcting for
instrumental delivery, duration of birth and episiotomy, may support an
actual effect of EA as the underlining cause of admission. These
findings may be in part explained by higher rates of neonatal
encephalopathy11 or seizures10 and
possible sepsis in mother and newborn with EA when maternal fever
occurred, or with respiratory depression, e.g. due to opioid
adjuncts.24 Unfortunately, NICU admission diagnoses
are not documented in the registry, which makes it difficult to
elucidate reasons and rationale explanations of the role of EA,
especially with lack of information on the drugs applied. There was no
association between overall perinatal mortality and EA in our
collective, and an impact on mortality could generally be assumed to be
more likely by secondary complications instead of EA itself. Hasegawa et
al. stated that morbidity as assessed by pH and APGAR scores were
associated with instrumental delivery, regardless of EA being used or
not.25
The rate of instrumental delivery with vacuum or forceps was more than
twofold increased in deliveries with EA (13.5% vs. 29.8%). Higher
proportions of women experienced instrumental delivery with EA in a
recent Cochrane review, although when studies conducted before 2005 were
excluded, no difference was present
anymore.3The authors direct this finding to modern techniques, e.g. low
concentration of local anesthetics, intermittent bolus application and
patient controlled analgesia. In a 2013 published meta-analyses
comparing low with higher concentration of local anesthetics for EA, the
use of low concentrations, i.e. ropivacaine ≤0.17% or bupivacaine
≤0.1%, was also associated with a reduction in assisted vaginal
delivery. When low concentration EA was compared with nonepidural
analgesia, Wang et al. could not demonstrate any difference in
instrumental delivery rates or prolonged second stage of labour in a
2017 published
meta-analysis.26Importantly, the authors stated that also low-quality studies were
included, with an overall decline in quality and certainty of the
conclusions drawn. If EA was directly related to the tremendously higher
rate of instrumental delivery in our study population, it may be due to
divergence of practice from universally accepted guidelines in modern
obstetric
anesthesia.14Also, obstetricians may attempt an instrumental vaginal delivery more
liberally with successful EA in place, leading to an increased number of
difficult deliveries in the EA group. Wassen et al. showed that with
increasing EA rates from 7.7% to 22% over ten years in the
Netherlands, no similar increase in instrumental delivery was
accompanied,27questioning the role of EA as a risk factor. Instrumental delivery is a
known risk factor for higher grade perineal
lacerations,28,29 although the differences between
groups in our study were quite close (2.8 vs. 3.2%) and are comparable
to the literature30–32 even with a more than twofold
higher instrumental delivery rate with EA. The effect of EA on perineal
lacerations is controversially reported, depending on the collective
with beneficial,28,31,33 negative34or no impact.3 In women with vaginal birth receiving
low dose combined spinal-epidural analgesia for vaginal birth, no
association with neuraxial analgesia could be shown.35
The duration of labour was also markedly prolonged in the EA group.
These findings differ from recent literature, describing an acceptable
prolongation of the second stage of
labour23,36or even no effect with low
concentrations.26Still, the data of the National Registry gives no information on
distinct stages and the timepoint of EA, hindering meaningful
comparisons. The low EA rates let assume, that the choice of epidural
use is more likely due to underlying circumstances of labour progress
than the women’s choice, making it more likely that EA was used in
already prolonged labour cases.
Conclusion
The results of this population-based registry study showed, that EA is
only administered in 20% of nulliparous women undergoing a singleton
vaginal delivery. For the primary outcomes pH and BE in umbilical cord
blood, no worse short-term outcomes for neonates were associated with
use of EA. The association of EA with increased NICU admission rates and
Apgar scores below 7 after 5 minutes are most likely related to
different indications for the use of neuraxial analgesia. Further
insight into a causal relation between EA and neonatal outcome can only
be gained when EA is applied independently of cervical dilatation,
labour progress and underlying circumstances that led to these
comparably low EA rates. A discussion on EA might enhance visibility and
thereby improve the quality of care in obstetric anesthesia in Austria.
Disclosure of
interests
The authors have no conflict of interest to declare.
Contribution to
authorship
FK was involved in drafting and reviewing the manuscript, as well as
gathering, analysing and interpreting the data. PW contributed in data
analysis, writing and reviewing the final manuscript. ELM performed the
statistical analysis and gave advice and input on data interpretation
including review of the manuscript. HH helped design and direct the
study, as well as manuscript revision. HL provided the data and was
involved in drafting and revision of the manuscript. HK designed the
study and organised the initiation and collaboration of all
participating authors. He gave advice on data interpretation and was
involved in drafting the manuscript. SJ gave valuable input in data
interpretation and reviewed the draft and final manuscript. CMO helped
with concept and writing of the manuscript, and gave advice on data
interpretation. KUK was responsible for the design of the protocol, data
interpretation, manuscript revision, and coordination of the research
team.
Details of ethics
approval
All analyses and gathering of data were initiated after approval
(EK Nr: 1576/2018) by the ethics committee of the Medical University of
Vienna, Austria (Chairperson Dr. Juergen Zezula) on 8 August 2018.
Funding
No funding, financial support or sponsorship was received.
Acknowledgements
Assistance with the study: none
Presentation: preliminary data for this study were presented as a poster
presentation at the Euroanaesthesia meeting, 1-3 June 2019, Vienna.
References
1.
Sng BL, Kwok SC, Sia ATH. Modern neuraxial labour analgesia. Curr
Opin Anaesthesiol 2015;28:285–9.
2. Eidelman AI, Hoffmann NW, Kaitz M. Cognitive deficits in women after
childbirth. Obstet Gynecol 1993;81:764–7.
3. Anim-Somuah M, Smyth R, Cyna A, Cuthbert A. Epidural versus
non-epidural or no analgesia in labour. Cochrane Database Syst
Rev 2018;5:CD000331.
4. Capogna G, Camorcia M, Stirparo S. Expectant fathers’ experience
during labor with or without epidural analgesia. Int J Obstet
Anesth 2007;16:110–5.
5. Jouppila P, Jouppila R, Hollmén A, Koivula A. Lumbar Epidural
Analgesia to Improve Intervillous Blood Flow During Labor in Severe
Preeclampsia. Obstet Gynecol 1982;59:158–61.
6. Hawkins JL. Epidural Analgesia for Labor and Delivery. N Engl J
Med 2010;362:1503–10.
7. Sultan P, Murphy C, Halpern S, Carvalho B. The effect of low
concentrations versus high concentrations of local anesthetics for
labour analgesia on obstetric and anesthetic outcomes: a meta-analysis.Can J Anesth 2013;60:840–54.
8. Sultan P, David AL, Fernando R, Ackland GL. Inflammation and
Epidural-Related Maternal Fever: Proposed Mechanisms. Anesth
Analg 2016;122:1546–53.
9. Lieberman E, O’Donoghue C. Unintended effects of epidural analgesia
during labor: A systematic review. Am J Obstet Gynecol2002;186:S31–68.
10. Greenwell EA, Wyshak G, Ringer SA, Johnson LC, Rivkin MJ, Lieberman
E. Intrapartum temperature elevation, epidural use, and adverse outcome
in term infants. Pediatrics 2012;129:e447–54.
11. Törnell S, Ekéus C, Hultin M, Håkansson S, Thunberg J, Högberg U.
Low Apgar score, neonatal encephalopathy and epidural analgesia during
labour: A Swedish registry-based study. Acta Anaesthesiol Scand2015;59:486–95.
12. Nielsen PE, Erickson JR, Abouleish EI, Perriatt S, Sheppard C. Fetal
Heart Rate Changes After Intrathecal Sufentanil or Epidural Bupivacaine
for Labor Analgesia: Incidence and Clinical Significance. Anesth
Analg 1996;83:742–6.
13. IET - Institut für klinische Epidemiologie. Bericht Geburtenregister
Österreich Geburtsjahr 2017. 2018.
https://www.iet.at/data.cfm?vpath=publikationen210/groe/
groe-jahresbericht-2017. Accessed 5 December 2019.
14. Oji-Zurmeyer J, Ortner CM, Klein KU, Gries M, Kühn C, Schroffenegger
T, et al. National survey of obstetric anaesthesia clinical practices in
the republic of Austria. Int J Obstet Anesth 2019;39:95–8.
15. von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke
JP. The Strengthening the Reporting of Observational Studies in
Epidemiology (STROBE) statement: guidelines for reporting observational
studies. J Clin Epidemiol 2008;61:344–9.
16. Buuren S van, Groothuis-Oudshoorn K. mice : Multivariate Imputation
by Chained Equations in R. J Stat Softw 2011;45.
17. Blondel B, Coulm B, Bonnet C, Goffinet F, Le Ray C, National
Coordination Group of the National Perinatal Surveys. Trends in
perinatal health in metropolitan France from 1995 to 2016: Results from
the French National Perinatal Surveys. J Gynecol Obstet Hum
Reprod 2017;46:701–13.
18. Waldenström U, Ekéus C. Risk of obstetric anal sphincter injury
increases with maternal age irrespective of parity: A population-based
register study. BMC Pregnancy Childbirth 2017;17:1–10.
19. Gilstrap LC, Leveno KJ, Burris J, Williams ML, Little BB. Diagnosis
of birth asphyxia on the basis of fetal pH, Apgar score, and newborn
cerebral dysfunction. Am J Obstet Gynecol 1989;161:825–30.
20. Martínez AH, Almagro JJR, García-Suelto MM-C, Barrajon MU, Alarcón
MM, Gómez-Salgado J. Epidural Analgesia and Neonatal Morbidity: A
Retrospective Cohort Study. Int J Environ Res Public Health2018;15:1–10.
21. Bodner-Adler B, Bodner K, Kimberger O, Wagenbichler P, Kaider A,
Husslein P, et al. The effect of epidural analgesia on the occurrence of
obstetric lacerations and on the neonatal outcome during spontaneous
vaginal delivery. Arch Gynecol Obstet 2003;267:130–3.
22. Reynolds F, Sharma SK, Seed PT. Analgesia in labour and fetal
acid-base balance: a meta-analysis comparing epidural with systemic
opioid analgesia. BJOG An Int J Obstet Gynaecol2002;109:1344–53.
23. Liu EHC, Sia ATH. Rates of caesarean section and instrumental
vaginal delivery in nulliparous women after low concentration epidural
infusions or opioid analgesia: systematic review. Br Med J2004;1–6.
24. Kumar M, Chandra S, Ijaz Z, Senthilselvan A. Epidural analgesia in
labour and neonatal respiratory distress: A case-control study.Arch Dis Child Fetal Neonatal Ed 2014;99:F116–9.
25. Hasegawa J, Farina A, Turchi G, Hasegawa Y, Zanello M, Baroncini S.
Effects of epidural analgesia on labor length, instrumental delivery,
and neonatal short-term outcome. J Anesth 2013;27:43–7.
26. Wang T-T, Sun S, Huang S-Q. Effects of Epidural Labor Analgesia With
Low Concentrations of Local Anesthetics on Obstetric Outcomes: A
Systemic Review and Meta-analysis of Randomized Controlled Trials.Anesth Analg 2017;124:1571–80.
27. Wassen MML, Hukkelhoven CWP, Scheepers HCJ, Smits LJM, Nijhuis JG,
Roumen FJME. Epidural analgesia and operative delivery: a ten-year
population-based cohort study in the Netherlands. Eur J Obstet
Gynecol Reprod Biol 2014;183:125–31.
28. Jangö H, Langhoff-Roos J, Rosthøj S, Sakse A. Modifiable risk
factors of obstetric anal sphincter injury in primiparous women: A
population-based cohort study. Am J Obstet Gynecol2014;210:59.e1-6.
29. Loewenberg-Weisband Y, Grisaru-Granovsky S, Ioscovich A, Samueloff
A, Calderon-Margalit R. Epidural analgesia and severe perineal tears: A
literature review and large cohort study. J Matern Neonatal Med2014;27:1864–9.
30. Vale de Castro Monteiro M, Pereira GMV, Aguiar RAP, Azevedo RL,
Correia-Junior MD, Reis ZSN. Risk factors for severe obstetric perineal
lacerations. Int Urogynecol J 2016;27:61–7.
31. Myrick TG, Sandri KJ. Epidural Analgesia and Any Vaginal Laceration.J Am Board Fam Med 2018;31:768–73.
32. Samuelsson E, Ladfors L, Wennerholm UB, Gåreberg B, Nyberg K,
Hagberg H. Anal sphincter tears: prospective study of obstetric risk
factors. BJOG An Int J Obstet Gynaecol 2000;107:926–31.
33. D’Souza JC, Monga A, Tincello DG. Risk factors for perineal trauma
in the primiparous population during non-operative vaginal delivery.Int Urogynecol J 2019;1–5.
34. Gundabattula SR, Surampudi K. Risk factors for obstetric anal
sphincter injuries (OASI) at a tertiary centre in south India. Int
Urogynecol J 2018;29:391–6.
35. Xing J-J, Liu X-F, Xiong X-M, Huang L, Lao C-Y, Yang M, et al.
Effects of Combined Spinal-Epidural Analgesia during Labor on Postpartum
Electrophysiological Function of Maternal Pelvic Floor Muscle: A
Randomized Controlled Trial. PLoS One 2015;10:1–10.
36. Halpern SH, Muir H, Breen TW, Campbell DC, Barrett J, Liston R, et
al. A Multicenter Randomized Controlled Trial Comparing
Patient-Controlled Epidural with Intravenous Analgesia for Pain Relief
in Labor. Anesth Analg 2004;99:1532–8.
Table 1: Demographic and delivery
characteristics