Topical benzoyl peroxide is generally considered safe to use during pregnancy. ACOG and the American Academy of Dermatology (AAD) list it among the first-line, preferred options for treating acne while pregnant. Only about 5% is absorbed through the skin and it's broken down and cleared quickly, so it isn't expected to reach the baby in meaningful amounts.
Benzoyl peroxide is a common over-the-counter treatment for acne, sold as gels, washes, and creams (usually 2.5% to 10%). It works by reducing acne-causing bacteria and clearing pores. When applied to the skin, only a tiny fraction is absorbed into the body, and it is metabolized into benzoic acid, which the body clears normally. This is different from oral acne medicines, which reach the whole body far more.
The American Academy of Dermatology (AAD) lists topical benzoyl peroxide among the treatments generally considered acceptable for acne in pregnancy, largely because of its minimal absorption. There have been no large controlled trials in pregnant people, so authorities describe the risk as low rather than proven zero. Because of this limited data, sources like the AAD and NHS still recommend using the smallest effective amount and speaking with your provider. It is not in the same category as retinoids (such as topical tretinoin/adapalene) or oral isotretinoin, which are advised against or contraindicated in pregnancy.
Stick to normal over-the-counter strengths on limited areas rather than covering large portions of skin, and avoid combining it with prescription retinoids unless your provider approves. If you prefer alternatives, the AAD notes that topical azelaic acid and topical/oral erythromycin are also commonly considered options for acne in pregnancy. Stop and contact your provider if you notice significant skin irritation, and always confirm any acne routine with your obstetric or dermatology provider.