10 month old with dark blue stain on tooth?

[WeeKirkie]

My baby got 2 teeth through when he was 6 months and the 2 on the top have come through recently. A couple of days ago I noticed one of the bottom teeth had a blue circular stain on it nearly covering the whole tooth! Tried and tried to scrub it off but it seems to be part of it. He is allergic to milk so is on neocate formula and I assumed it was a calcium problem. Seen the dietician today, who said they had never seen it before and recommended going to the doctor. Has anyone had this experience before? He doesnt eat sweets, or drink fruit juice so doubt it could be tooth decay. Thank you in advance for any help!

I have heard that stains can be the result of antibiotics during pregnancy. Is there any chance you took some before you found out?

Actually I had to take really strong antibiotics for constant kidney infections through my pregnancy, but was told it wouldnt affect my baby. So you could be right going to the doctors tomorrow will bring this up and see what he says about it. Thank you!

I only know that because forty plus years ago, our neighbours' daughter's first teeth were stained by antibiotics taken by her mother during pregnancy. But it was only her first teeth and these days you could get veneers.