I used hydroquinone during the first 8 weeks of pregnancy, should I be concerned about how this may affect my baby?

Hi!  Congratulations on your pregnancy.   Hydroquinone is considered a 'class C' drug in pregnancy.  This means that no human and animal studies have show an adverse effect.  It's safely profile is 'uncertain'.  With medications and pregnancy, the FDA errors on the side of caution (rightly so) so it takes a lot for a medication to be officially deemed 'safe' in pregnancy.   Also, your use was topical (not ingested) so it's unlikely that any significant dose got into your blood stream to affect the developing fetus. You should definitely let your ob MD know that you were using hydroquinone but has since stopped.  Once again, congratulations!  Dr. Huo