There's no conclusive evidence that tanning beds are harmful to a developing fetus, but there is plenty of proof that they're dangerous to you, namely by increasing your risk of developing skin cancer. Lying in a tanning booth can also raise your body temperature to a level that may be hazardous to your baby, particularly during your first trimester. Never mind that hormone changes might mean that your skin tans unevenly or that you develop large brown patches known as melasma. If you're looking for a sun-kissed glow, try a self-tanner, which is harmless to both you and your baby.