5 theories why pregnant women are turning toilet seats blue

Posted in Conception.

If you haven’t heard about the pregnant lady blue toilet seat phenomenon – aka Smurf Butt -then pull up a chair and let us tell you more.

Smurf Butt?

So. A gent took to the Stack Exchange Chemistry forum to share something that had happened at his house.

“My partner is pregnant, and thought perhaps she was going mad when one day she found our toilet seat had turned blue,” the man wrote.

“After some investigation, it seems this is a real phenomenon, see here for a nice example, with the image from this link shown below.”

(We’ve popped it below for readers to examine.)

So why is this lady’s toilet seat blue?

What about her pregnancy has these amazing colour changing powers?!

The man in question shared some theories, as did others on this forum and countless others.

Theory one

Dye from maternity jeans has transferred from the pregnant mum’s legs to the toilet seat.

The dad-to-be debunked this. He said that she’s been wearing the same jeans for months and the loo seat has never turned blue before.

Someone on Reddit chimed in (on a separate post about this phenomenon) noting “it has happened to women that do not wear any pants that would apply to.”

“I know people have said it’s not a real thing, it’s from your clothes but that’s impossible! I don’t wear jeans,” a mum on What To Expect confirmed.

Theory two

Dye from medication or a colourful pregnancy supplement might be ‘leeching out’ in the mum’s sweat.

The dad-to-be says his partner is taking a particular medication which has been linked with this phenomenon. She’s also taking a blue pregnancy supplement.

Sounds promising but again, she’s been taking these for a while, so why the sudden blue hue?

Mysterious, non?!

Theory three

Body oils and sweat are taking on a blue hue, and it’s transferring.

There is a condition called Chromhidrosis which turns human sweat and body oils grey or blue. 

That could be it, but another person on the thread pointed out that if the pregnant woman was suffering from this, her clothing and bedsheets would be blue too. This was not the case for this couple.

“Hormone changes can cause temporary pseudochromhidrosis,’ that person noted. “This condition produces clear sweat which reacts with certain surface bacteria and the result on some surfaces is blue/purple staining. Only an acid based cleaner will remove it.” Woah.

Someone in another forum for women who were dealing with breast cancer favoured this blue sweat/oil theory too. A woman had piped up about her blue toilet seat and also wondered why it was changing colour.

A respondent to her post noted that taking B vitamins might also be causing this blue hue with B vitamin feeding the bacteria, which can cause the Chromhidrosis. Then those blue-ish body oils and sweat may interact with the toilet seat.

“Moral of the story-Vitamins are good for our body, not so much for toilet seats,” that person wrote.

Theory four

It’s not only related to pregnancy.

Okay. That’s not really a theory, more of an observation but we feel it’s valid.

“This happened to mine and I wasn’t even pregnant at the time!” one mum on Reddit revealed.

(The breast cancer poster we mentioned above was not pregnant.)

Blue toilet seat

Theory five

It could be related to blood sugar.

Another person on Reddit – posting in a Diabetes subreddit – who was also not pregnant said it was happening to her (and debunked many of the theories we mentioned above.)

“I have not worn any new jeans. We have not changed cleaning products (or used any directly prior to the blue color emerging). My butt is decidedly not blue. It gets darker after I sit on it. I was just put on Prednisone for asthmatic bronchitis, and I know this can seriously mess with my blood sugar,” she wrote, pondering if blood sugar was the culprit.

Blue Toilet Seat from diabetes

So we don’t know if it’s related to vitamin supplements, hormones or bacteria … But it does seem to be a thing and for some a predictor of pregnancy!

“I turned my toilet seat blue a few days before my missed period!” one mum posted on What To Expect. “I was freaking out because that’s only happened when I’ve been pregnant. That was my first clue to take a test lol.”

So if you got here by googling “blue toilet seat pregnant” know that you are not alone. And know that it’s not just pregnant women who experience Smurf Butt. 

You’re welcome!

Also? If you’re not pregnant and your toilet seat has turned blue … maybe it’s time to take a test!


Get more babyology straight to your inbox