Summer after sunny summer, you’ve been the model of sun protection. Right? But now that you’re pregnant (congrats!), shielding yourself from the sun's harmful ultraviolet, or UV, rays is more important than ever. Your body’s pigment-producing cells (called melanocytes) kick into overdrive during pregnancy, making your skin more susceptible to UV-induced discoloration. Plus, while sun exposure doesn’t directly affect your bun in the oven, sunburns can crank up that oven’s temperatures, says Joanne Stone, M.D., director of maternal fetal medicine at The Mount Sinai Hospital in New York City. (Elevated core temperatures during pregnancy have been linked to birth defects.) Follow these sun safety tips to protect your body and your baby.