I am currently pregnant with my second child and as in my first pregnancy, I am on PTU. My first daughter is as healthy and perfect as any parent could ask for, even though I was on PTU before conception and during the first 16-20 weeks of pregnancy. She also appears to have normal thyroid functions. My second pregnancy is going fine (I’m about 15 1/2 weeks) and take two doses of PTU a day. I did receive the RAI treatment between the two pregnancies. I’ve been in both situations (using PTU and having RAI) and both times have been fine. I conceived easily both times. The only thing is that after the RAI treatment, I waited 12 months to conceive.
Hope this info. helps and good luck!