Hi, I've done some research on this myself and apparently benxoyl peroxide (the active ingredient in proactiv) is classed as a category C drug- So far, there have been no studies on humans or animals that show risk correlations between benzoyl peroxide and pregnancy. See this link- Benzoyl peroxide and pregnancy This means the risk is still unknown. If I were you I would just check it with your doctor.

*edit* ooops I see you're going to use something else anyway! Good luck, I know how frustrating skincare can be!