Funny Toilet Seats Since I Have Been Pregnant The Toilet Seats In My House Keep Changing Blue, WHY?

Since I have been pregnant the toilet seats in my house keep changing blue, WHY? - funny toilet seats

My husband has replaced the head several times, all different types. The same is always done very quickly as it blue! Everyone thinks it's funny, and my doctor looked at me I was crazy, but what happens, and I want to know why. If it is dangerous, I think it's something that I shoulder ... Even if not, I'm always curious to know why.