Fake tan lotions, creams, and mousses are generally considered safe to use in pregnancy. The NHS says the active ingredient, DHA, is not thought to be harmful because very little is absorbed through the skin. The one exception is spray tans: the NHS suggests caution there, since it's unclear whether inhaling the spray mist is safe, so a lotion or cream is the better choice while you're pregnant.
Self-tanners create a tan without sun or UV exposure. The active ingredient is usually DHA (dihydroxyacetone), which reacts with amino acids in the outer, dead layer of your skin to turn it brown. The NHS notes this is largely a surface reaction, so very little is thought to be absorbed into the body when you use a cream, lotion, or mousse. This is different from tanning that comes from UV light or from pills taken by mouth.
For creams and lotions, the concern is low. The NHS and MotherToBaby indicate topical DHA sits mostly on the skin surface, and dermatologists generally consider these products acceptable in pregnancy. The bigger question is spray and aerosol tans: the NHS says the effects of breathing in the fine mist are not known, and inhaled DHA could reach the bloodstream. That uncertainty is why we lean cautious overall rather than a flat yes.
Choose creams, lotions, mousses, or drops over aerosol sprays and professional spray-tan booths, so you avoid inhaling the mist. Patch-test first, since pregnancy hormones can change how your skin reacts. Avoid tanning pills entirely, which the FDA has flagged as unsafe. If you want zero product exposure, a tinted moisturizer or gradual wash-off bronzer is a lower-commitment option.