Is it safe to take selenium sulfide while pregnant or breastfeeding?

No: Selenium sulfide is used in topical creams (for dermatitis, or "rash") and shampoos (notably selsun blue, for dandruff). The easy answer is yes and the complicated answer is no. The reason? It is categorized as "c" meaning there are no studies in pregnancy documenting it's safety. So, doctors say, "if the benefits outweigh the unknown risks, go ahead." so...Shampoo -- yes. Topical cream -- no.