Ethylene oxide-sterilised swabs won’t cause harm during pregnancy

28 September 2021
What was claimed

A Public Health England document shows that ethylene oxide, the sterilising solution used on PCR tests, may be harmful to the unborn child.

Our verdict

Prolonged exposure to ethylene oxide can be unsafe and may be harmful to the unborn child. But when it is used to sterilise test swabs it does not pose this risk even if you are tested often.

A post on Facebook shows a screenshot from the Public Health England (PHE) website about ethylene oxide, with an arrow pointing to a line that says “ethylene oxide may be harmful to the unborn child”. Text over the picture says “STERILE SOLUTION USED ON THE PCR TESTS”.

Ethylene oxide is a colourless gas that is used to sterilise medical equipment, including swabs used in Covid-19 test kits. We’ve written several times before about the fact that although high exposure to ethylene oxide can be unsafe, swabs are extremely unlikely to contain residual ethylene oxide on them from the sterilising process and this level of exposure won’t cause harm.

The UK regulator, the Medicines and Healthcare products Regulatory Agency (MHRA) says: “The sterilisation process consists of a number of highly controlled and monitored stages, including removing ethylene oxide after treating the swabs. The amount of residual EO that is allowed has been set...according to contact time of the medical device with the person. Contact time is divided into 3 categories: limited, prolonged, and permanent duration.

“The swabs used in lateral flow test kits fall under the category of limited contact time. These limits are not further divided by body weight and therefore the limits set are also applicable for children.”

It adds: “In the highly unlikely event that a swab does contain a residual amount above the allowable limit, the risk to the user is still considered to be very low.”

A minimal amount of ethylene oxide is used for sterilisation of the swabs—just 1-2μg (millionths of a gram) per gram.

The picture is of a genuine document on PHE’s website about how prolonged exposure to ethylene oxide can have serious health consequences. The document from PHE goes on to say there “is limited evidence to suggest that ethylene oxide may be toxic to the reproductive system and the unborn child”. 

But this is not the level of exposure you get from using the swabs in Covid-19 tests, even if you are tested often.

This article is part of our work fact checking potentially false pictures, videos and stories on Facebook. You can read more about this—and find out how to report Facebook content—here. For the purposes of that scheme, we’ve rated this claim as partly false because the amount of ethylene oxide you are exposed to by getting swabbed for Covid-19 tests is much lower than the levels the PHE document is referring to.

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