The Effectiveness of Entonox When Comparing to Pethidine for Labor Pain:

A Systematic Review


  • Thilini Nadeeshani Subasinghe University of Sunderland



Labour pain, best analgesia, Entonox, pethidine


Labour pain is considered as one of the most severe and intolerable pain in the world. Therefore several type of analgesia are used to relieve the labour pain. In 1934 Minnitt has intended a self-administration machine to inhale nitrous oxide. In England and both Asian and European countries have been using it for 60 years. Since 1950, pethidine is used in the England independently by the midwife to relieve the labour pain although it has a few side effects. This study was conducted to detect the best analgesia to manage labour pain among pethidine and Entonox. The aim of this study was to compare Entonox and pethidine to identify the most effective method to manage the labour pain. Systematic review of six primary quantitative studies, which were done according to the randomized control trial was conducted. Inclusion criteria were term, normal cephalic fetus in active phase of labour mothers who were having pethidine or nitrous oxide (Entonox) as labour analgesia. This study consisted of 596 participants worldwide. Findings reveal that Entonox helps to reduce the duration of labour, severity of labour pain and higher satisfaction than pethidine. In Conclusion, Entonox has more beneficial effects to relieve labour pain in the first stage of labour than pethidine.


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Abboud, T. K., Shnider, S. M., Wright, R. G., Rolbin, S. H., Craft, J. B., Henriksen, E. H., Johnson,

J., Jones, M. J., Hughes, S. C., & Levinson, G. (1981). Enflurane analgesia in obstetrics.

Anesth Analg, 60:133–7

Anderson, D. (2011). A review of systemic opioids commonly used for labor pain relief. Journal of

Midwifery and Women’s Health, 56, 222-239.

Attar, A. S., Feizabadi, A. S., Jarahi, L., Feizabadi,S. L., & Shebani, S. (2016), Effect of Entonox on

reducing the need for Pethidine and the Relevent Fetal and Maternal Complications for painless labour. Electron Physician, 81(12): 3325-3332.

Bamfield, T. (1997). Management of labour pain by midwives: a historical perspective. In: S.Moore

(Ed.). Understanding pain and its relief in labour, (Edinburgh, Scotland: Churchill Livingstone) pp. 63-76.

Bettany-Saltikov, J. (2010). Learning how to undertake a systematic review: part 2. Nursing Standard,

(51), 47-56.

. Biró, M. A., Waldenström, U. & Pannifex, J. H. (2000). Team midwifery care in a tertiary level

obstetric service: a randomized controlled trial. Birth, 27: 168-173.

Bishop, J. T. (2007). Administration of Nitrous Oxide in Labor: Expanding the Options for Women. J

Midwifery & Women’s Health, 52: 308-309.

Chapman, C. R. (1996). Limbic processes and the affective dimension of pain. Progre Brain Res,

:63- 81.

Collins, M. R., Starr, S. A., Bishop, J. T. & Baysinger, C. L. (2012). Nitrous oxide for labor analgesia:

expanding analgesic options for women in the United States. Reviews in Obstetrics & Gynecology, 5(3), 126–131.

Duthie, D. J. (1998). Remifentanil and tramadol. Br J Anaesth, 81(1):51–7.

[PubMed: 9771272].

Einarsson, S., Stenqvist, O., Bengtsson, A., Norén , H. & Bengtson, J. P. (1996). Gas kinetics during

nitrous oxide analgesia for labour. Anaesthesia , 51:449–52.

Faddy, S. C. & Garlick, S. R. (2005). A systematic review of the safety of analgesia with 50% nitrous

oxide: can lay responders use analgesic gases in the prehospital setting?. Emerg Med J, 22(12):901–8. doi:10.1136/emj.2004.020891. [PubMed: 16299211].

Goodson, C. & Martis, R. (2014). Pethidine: to prescribe or not to prescribe? A discussion

surrounding pethidine's place in midwifery practice and New Zealand prescribing legislation.

New Zealand College of Midwives Journal, 49, 24.

Harrison, R. F., Shore, M., Woods, T., Mathews, G., Gardiner, J. & Unwin, A. (1987). A comparative

study of transcutaneous electrical nerve stimulation (TENS), entonox, pethidine + promazine and lumbar epidural for pain relief in labor. Acta Obstet Gynecol Scand, 66:9–14

Hawkins, J. L. & Beaty, B. R. (1999). Update on obstetric anaesthesia practices in the US.

Anesthesiology 91: A1060.

Higgins, J.T., Altman, D. G. & Sterne, J. C. (2011). Chapter 8: Assessing risk of bias in included

studies. In: Higgins JPT, Green S, eds. Cochrane Handbook for Systematic Reviews of Interventions Version 510, The Cochrane Collaboration.

Khan, K., Kunz, R., Kleijnen, J., & Antes, G. (2011). Systematic reviews to support evidence- based

medicine. Crc Press.

Jantjes, L., Strumpher, J. & Kotze, W. (2007). The experience of childbirth [sic] infirst-time mothers

who received narcotic analgesics during the first stage of labour. Curationis, 30(2), 82-90. The CINAHL database:

Likis, F. E., Andrews, J. A., Collins, M. R., Lewis, R. M., Seroogy, J. J., Starr, S. A., Walden, R. R.

& McPheeters, M. L. (2012). Nitrous Oxide for the Management of Labor Pain. Comparative Effectiveness. Agency for Healthcare Research and Quality, 67.

Mander, R. (2010). Pain in childbearing and its control: key issues for midwives and women.

John Wiley & Sons.

Manouchehrian, N. & Bakhshaei, M. H. (2014). Nitrous oxide effect on relieving anxiety and pain in

parturients under spinal anesthesia for caesarean section. Anesthesiology and pain medicine, 4(2).

Melzack,, R. (1984). The myth of painless childbirth. Pain, 19(4), 321-337.

Mobaraki, N., Yousefian, M., Seifi, S. & Sakaku, M. (2016). A Randomized Control Trial Comparing

Use of Entonox with Pethidine for Pain Relief in Primigravid Women Durin the Active Phase of Labor. Anesth Pain Med, (In Press): e 37420.

Morgan, B., Bulpitt, C.J., Clifton, P. & Lewis, P. J. (1982). Effectiveness of pain relief in labour:

survey of 1000 mothers. Br Med J, 285:689–90

Muslih, H. A., Ismael, A. H. & Raoof, E. (2010). Analgesia in labor: Evaluating clinical trial

comparing between Entonox versusparenteral pethidine during the first stage of labor. Mustansiriya Medical Journal, 10 (1).

McDonald, J. S. (2001). Pain of child birth. In, Loser J D Bonican’s. Management of pain. 3rd ed.

(Philadelphia: Lippincott Williams and Wilkins), PP. 1388-414.

Najefian, M., Cheraghi, M., Pourmehdi, Z. & Nejad, A. D. (2013). The effect of nitrous oxide

(ENTONOX) on labour pain relief during delivery stages. International Journal of Pharmacy & Therapeutics, 4, 242–246.

NEW ZEALAND MINISTRY OF HEALTH, Pethidine Hydrochloride Injection. Administering the

medicines 2012. Available from: http://

Olofsson, C., Ekblom, A., Ekman-Ordeberg, G., Hjelm, A. & Irestedt, L. (1996). Lack of analgesic

effect of systemically administered morphine or pethidine on labour pain. Br J Obstet

G`ynaecol, 103(10): 968–72. [PubMed: 8863693].

Ommanouil, D. E. & Quock, R. M. (2007). Advances In understanding the action of nitrous oxide.

Anesh Prog, 54(1), 9-18.

Pasha, H., Basirat, Z., Hajahmadi, M., Bakhtiari, A., Faramarzi, M. & Salmalian, H. (2012). Maternal

expectations and experiences of labor analgesia with nitrous oxide. Iran Red Crescent Med J. 14(12): 792–7. doi: 10.5812/ircmj.3470. [PubMed: 23483128].

Petticrew, M., & Roberts, H. (2008). Systematic reviews in the social sciences: A practical guide.

John Wiley & Sons.

Rooks, J. P. (2011). Safety and risks of nitrous oxide labor analgesia: a review. J Midwifery Womens

Health, 56: 557–65.

Rosen, M. A. (2002). Nitrous oxide for relief of labor pain: a systematic review. Am J Obstet Gynecol

: S110– 26.

Sosa, C., Buekens, P., Hughes, J., Balague, E., Sotero, G., Panizza, R., Piriz, H. & Alonso, J. (2006)

Effect of pethidine administered during the first stage of laboron the acid–base status at birth. European Journal of Obstetrics & Gynecology and Reproductive Biology, 129, 135–139. doi:10.1016/j.ejogrb.2005.11.033

Squire, C. (2000). Pain relief: past and present. In: Yerby, M. (Ed.). Pain in childbearing: key issues in

management. (London, England: Harcourt Publishers Ltd) pp. 1-16.

Stefani, S. J., Hughes, S. C., Schnider, S. M., Levinson, G. & Abboud, T. K. (1982). Neonatal

neurobehavioral effects of inhalation analgesia for vaginal delivery. Anesthesiology, 56: 351-355.

Tazarjani, F. Z., Sekhavat, L. & Karimzadeh Mibodi, L. (2010). The effect of continuous entonox

inhalation on the length of labor in duration of active phase of labor, Journal of Babol University of Medical Sciences, 11( 6), pp. 21–25.

Teimoori, B., Sakhavar, N., Mirteimoori, M., Narouie, B. & Ghasemi-rad, M. (2011). Nitrous oxide

versus pethidine with promethasine for reducing labor pain. Afr J Pharm Pharmacol, 5(17): 2013-17.

Thomson, A. & Hillier, V. (1994). (2012). A re-evaluation of the effect of pethidine on the length of

labour. Journal of Advanced Nursing, 19, 448-456. CINAHL database:

Tsui, M. H., Kee, N., Warwick, D., F. & Lau, T. K. (2004). A Double blinded Randomised

placebo‐controlled study of Intramuscular Pethidine for Pain Relief in the first stage of Labour. BJOG: an international journal of obstetrics & gynaecology, 111(7), 648-655.

Tuckey, J. P., Prout, R. E. & Wee, M. Y. (2008). Prescribing intramuscular opioids for labour

analgesia in consultant-led maternity units: a survey of UK practice. International journal of obstetric anesthesia, 17(1), 3-8.

Wang, F., Shen, X., Guo, X., Peng, Y. & Gu, X. (2009). Labor Analgesia Examining Group. Epidural

analgesia in the latent phase of labor and the risk of caesarean delivery: a five-year randomized controlled trial. Anesthesiology. 111: 871-880.

Waters, A. (1947). Pethidine in labour. British Medical Journal, 2 (4514), 71-2.

Retrieved October 10, 2012 from the US National Library of Medicine website:

Waud, B. & Waud, D. (1970). Calculated Kinetics of Distribution of Nitrous Oxide and

Methoxyflurane during Intermittent Administration in Obstetrics. Anesthesiology, 32(4):306–316, APRIL 1970 . PMID: 5437861

Wee, M. Y., Tuckey, J. P., Thomas, P. & Burnard, S. (2011). A two-centre randomised double-blind

controlled trial comparing intramuscular diamorphine and intramuscular pethidine for labour.

Analgesia, 11:51.

Yerby, M. (2000). Pharmacological methods of pain relief. In: Yerby, M. (Ed.).Pain in childbearing:

key issues in management. (London, England: Harcourt Publishers Ltd), pp. 111-130.




How to Cite

Subasinghe, T. N. (2020). The Effectiveness of Entonox When Comparing to Pethidine for Labor Pain:: A Systematic Review. Proceedings of the International Conference on Public Health, 5(2), 8–18.