If it is what I think it is it can cause miscarriage

I actually just came from the dermotologist and she said that until recently, it was thought that pityriasis rosea had no dangerous effects for pregnant women and their babies. However, a recent study (not much of a study from the sounds of it, only 38 people tested) showed some issues with muscle density in the baby and some issues with miscarrieage if the pityriasis presented within the first 15 weeks of pregnancy. I can't really vouch for the study. As I said, they only tested about 38 people in the study and my doctor didn't seem all that terribly concerned. You might want to consult and ObGyn. They would definitely know better than I would.