Obstetric Analgesia and Anesthesia

last authored: Oct 2011, David LaPierre
last reviewed:

 

 

Introduction

Pain is a usual significant symptom during labour and delivery, though a wide variation in experience exists. Women should understand their normal response to pain and anticipate their strategies, though labour pain cannot reliably be predicted. Reaching the limits of pain tolerance can lead to high levels of stress hormones, which can decrease uterine contractility. This, in turn, can cause decreased progress, leading to anxiety and a worsening of the experience. Analgesia, which can occur in many ways, can allow release from this harmful cycle.

 

Visceral pain during labour from the uterus and cervix is transmitted by spinal nerves T10-L1. Somatic pain from pressure on the vagina and perineum is transmitted by the pudendal nerve (S2-S4).

 

Active involvement of caregivers can help reduce the pain experience, as has been known for many years. This begins before labour with a discussion regarding expected and possible events during labour and delivery, as well as analgesia options and side effects. During labour, the ongoing presence of a health provider with a calm, confident attitude can do much to calm and relax a mother in pain; indeed, it has been said that "a competent, unharassed mid-wife who has time to chat with the patients is the greatest boon in normal childbirth" (Crawford, 1966).

 

Health care providers should have a thorough knowledge of pain control pharmacology and side effects. No drug is completely risk-free, and efforts should be taken to prevent toxicity to mother and infant. Pain relief should be provided according to the mother's request, if contraindications do not exist. However, many women prefer not to use medications during labour, and they should be supported with effective non-pharmacologic options.

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Non-Pharmacological Techniques

Active involvement of caregivers can help reduce the pain experience. This begins before labour with a discussion regarding analgesia options, including side effects. Many women prefer not to use medications during labour, and they should be supported with effective non-pharmacologic options.

 

Painful stimuli can be reduced by changing positions, ongoing movement, the hands and knees position, and upright positions in women who have not had epidural analgesia. A birthing ball can be helpful for movement and positions.

 

Touch and massage can be helpful for many women, and counter pressure may also be used. The birth attendant or partner pushes at or just above the sacrum, usually during the contraction. This may be facilitated by a hands and knees position. Some women, however, may find touch or massage irritating and unpleasant.

 

Superficial heat and cold may also be used. Immersion in water is associated with decreased rate of regional anagesia, though it is unclear what causes this effect. A birthing tub can be used for immersion.

 

Sterile water injections intradermally can decrease pain and Caesarean section rate. While safe and easy, these injections are initially incredibly painful, which may cause hesitation of use for providers or patients.

 

Other methods to consider include:

 

 

Medications

Pharmacotherapeutic pain relief should be provided according to the mother's request, if contraindications do not exist and medications are available.

  • nitrous oxide
  • opioids
  • peripheral blocks
  • regional analgesia

Nitrous Oxide

Nitrous oxide (NO) is often used for women who have done well without pain control until transition to the second stage and then require a short course of pain control. Deep breaths should be given as soon as a contraction begins and stopped once the contraction subsides.

 

 

 

Resources and References

Crawford JS. 1966. Obstetric analgesia and anaesthesia - the current scene. Postgrad Med J. 42: 351.

Wang F et al. 2009. Epidural analgesia in the latent phase of labour and the risk of Caesarean deliveyr; a 5-year RCT. Anesthesiology. 111(4):871-80.

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