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Use of Entonox in our maternity unit

Posted: 27 February 2023

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Entonox is a mixture of nitrous oxide and air which is used as pain relief for women in labour.

There have been reports in the media about some NHS trusts suspending the use of Entonox over concern about how levels of waste gas might affect staff in maternity units.

We have never suspended the use of Entonox and have been carefully monitoring nitrous oxide levels since we became aware of the issue in October 2021.

The infrastructure of our estate means we cannot put a mechanical ventilation system in place but we have installed machines which effectively remove waste anaesthetic gas from delivery rooms ensuring safety for our patients and staff.

If you have any concerns, please talk to your midwife.


  1. For more information, please contact the communications team on: 01923 436280 or email: For out of hours media enquiries please call the Watford General Hospital switchboard on 01923 244366 and ask for the on call communications manager.
  2. West Hertfordshire Teaching Hospitals NHS Trust serves people from across Hertfordshire, north London and further afield. It operates from three hospitals; Watford General, St Albans City and Hemel Hempstead. The trust has a catchment area of over 500,000 people and is one of the largest employers locally, with around 5,000 staff and volunteers.
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