Pain relief options for labour – Pharmacological

Most of us would like to give birth in the most natural way possible, but sometimes circumstance dictate the need, or wish for other methods of pain relief during labour.

Labour pain

When you feel you need something else for the pain these are the most commonly used methods.

Gas and Air (Entonox)

Gas and air is an inhalational pain relief method given either by mask or a mouthpiece. It is a combination of Nitrous Oxide 50% and oxygen 50%. It dulls your perception of pain by preventing your nerve cells communicating with each other. Deep breaths should be taken from the onset of your contractions so that it has time to take effect by the time you reach the peak of your contraction by approximately 30 seconds.


  • Self administered so you remain in control
  • It is the safest inhaled gas available, and has no known adverse side effects to either you or your baby
  • Can be used in conjunction with other methods of pain relief
  • It does not slow down the progress of labour
  • It is available throughout the UK in most hospitals
  • Safe to use for a homebirth and/or water births


  • May cause initial dizziness when you start to use it
  • Can also cause nausea and mouth dryness
  • Will only give partial pain relief
  • Overuse may make you feel drowsy or emotional

When do I use it?

  • Early in the first stage of labour as an interim measure for other analgesia to take effect
  • During uncomfortable procedures such as a vaginal examination
  • At the latter stages of labour when other pain relief methods are unsuitable

Amanda’s Tips:

  • Try out both the mask and the mouthpiece to see which you prefer
  • It is worth persevering even if you do not like the initial sensation
  • Start breathing the gas and air from the very beginning of your contraction for maximum effect
  • Keep well hydrated and use lip balm to prevent your lips drying and cracking

TENS (Transcutaneous Electrical Nerve Stimulation)

TENS is a method of electrical stimulation used to excite your sensory nerves and provide a degree of pain relief. It works through the ‘gate control’ theory whereby it closes the gate to the pain sensors in the brain. It also stimulates your body to produce your own natural endorphins (pain killers).

How do I use it?

The TENS unit consists of a small unit about the size of a mobile phone with leads which you connect to four rubber electrode pads.

These are placed on your back as per instructions and taped in place. When it is turned on you will experience a tingling sensation under the electrodes. The unit operates in two modes:

  • Pulsing for low level pain
  • Constant for acute pain such as a contraction


  • Non invasive and easy to use
  • Self administered therefore you are in control
  • You can remain mobile
  • No major side effects for you or your baby
  • It does not slow down the progress of labour
  • Relatively inexpensive and easy to hire or buy yourself
  • It can be used in conjunction with other forms of pain relief, and reduce the amount of other analgesia needed


  • It will not totally eradicate labour pains
  • It is not suitable to use in water
  • Maximum endorphin levels not reached for at least 40 minutes after it is switched on
  • May cause an allergic skin reaction in a few women (approx 2%) from either electrodes, gel or tape used
  • May become an irritation rather than a relief in labour

Amanda’s Tips:

  • Hire or buy your TENS at least four weeks before your due date
  • Start using the TENS machine early in labour for maximum benefit
  • Have a spare battery handy
  • Practice using your machine before labour starts (do not use before 34 weeks gestation)

Photography: Bradley Gordon @Flickr

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