Hydroquinone is unlicensed in the UK but is used topically for skin de-pigmentation in the treatment of conditions such as melasma (chloasma) and vitiligo. It is also used in black and white photographic developers as a reducing agent. Extremely limited data are available regarding pregnancy outcome following exposure to hydroquinone and human data on which to assess teratogenic risk are lacking. 

As with all chemicals, unnecessary exposure should be avoided. The use of hydroquinone-containing skin lightening preparations during pregnancy is not recommended. Where occupational exposure is unavoidable, precautions should be taken to ensure that exposure is well within the recommended exposure limits and not associated with toxic symptoms. Protective clothing should be worn and the work area should be adequately ventilated.

Exposure to hydroquinone at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy, but due to the lack of data the need for additional fetal monitoring should be considered on a case-by-case basis. Other risk factors may also be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.