I had the same problem but with skincare products. I had a facial when I was 6 weeks preg at the salon I used to work at with the same products I have used for the past 6 years and the next day my face came out in a big rash. I worked out which product I had the reaction to and didn't use it for the rest of my pregnancy, but have used it since with no problems at all. On the up side though, my eczema was much better during my pregnancy and almost disappeared. Unfortunately it has come back since with avengeance!