Is it harmful to use Retin-A while pregnant? Ive used it for the first four months and im freaking out?

ive read mixed things, how its pregnancy category C, which means it could be harmful to a fetus or there has not been enough testing, etc. i know that vit A taken internally has been proven to cause birth defects, but does anyone know firsthand if topical gel really harms a fetus? ive been googling it all day and get contradicting answers: basically, has anyone used this while preg and is your baby normal? im terrified about this. thanks =(