Weird poop😂

Shiara • Im an 18 year old FTM, engaged to the love of my life, the beautiful man who gave me my perfect little son 😍 15/18/16💙
I cant believe im posting this.. Omg. 
So im 33w pregnant and just took a poop FINALLY but it smelt like a metal kindof smell.. I read somewhere previously that it has something to do with a certain vitamin or something, but im wondering what one? Does anyone know? I dont remember.
If im not getting enough of something, id like to fix it because of the baby. 
Thanks in advance :)