Toilet Seat Turning Blue Because of Pregnancy?

So...this seems to be a new one.

The toilet seats my very pregnant wife uses are turning blue.

The Internet, usually rife with solutions, is coming up with almost nothing on this very strange side effect that seems to come from pregnancy. Nothing on YouTube. Very little out there on the old Google search. I couldn't find any references to anything where anyone said with finality where this strange anomaly may be coming from.

Mamiverse.com included it in a 2012 article about bizarre pregnancy things that we need not worry about. They identified that it happened, not how or why.

It could also be blamed on hormones—and why not, since they’re the cause of so much other bodily mayhem during pregnancy. Whatever the cause, this unusual symptom seems harmless enough, and sure makes for a better story than stretch marks.

The Bump has a full forum about it, but no real answers. There was speculation that it might be because of dye in prenatal vitamins, but then a woman who had the blue ring around the toilet siad that she was taking very few prenatals and the ones she took didn't contain any dye. Plus, she's having trouble cleaning it.

I've tried all the cleaning products (including magic eraser). Nothing. The worst part is I can only find anecdotal stories via the Internet. L&D nurse and docs really didn't know what I was talking about (I called in case this could be indicative of something more serious) so it's still just the Internet.

So, it's all speculation and conjecture. No one knows what is happening. I found stilll another site with both pregnant and non-pregnant people talking about this issue. One person went pretty scientific on a theory about this phenomenon.

After much Googling my theory is that the ionized silver anti-microbial coating on the toilet seats is being turned into silver salts by sweat during pregnancy (Probably by higher acidity caused by sweating out something: excess proteins, vitamin supplements, etc.). These silver salts are then exposed to light as in a gelatin silver print and over an hour or so are resulting in an even deposit of microscopic deposits of silver as a film across the seat. The process being similar to what happens in argyria, a blue-grey pigmentation of the skin caused by absorption of silver into the body. The microscopic deposits of silver will not return to their prior state and are not going to be bleached away. You would have to use acid so they are likely to be there for good. For non silver anti-microbials there is a dye called bromophenol blue which is a absorbed by some of the coatings but I prefer the silver deposit theory as I suspect silver anti-microbials are more common on toilet seats.

Does anyone have any insight on this situation?