It is very common for pregnancy mummies to develop dark spots on their skin, thanks to hormonal changes. Unfortunately, direct exposure to sunlight can trigger it, or exacerbate existing spots. If you have to be in the sun, be sure to wear a large brim hat, and be generous with your SPF cream.
If in doubt, ask. Get advice from your doctor, your dermatologist and your beauty therapist if you need any pointers on pregnancy friendly cosmetics, products and beauty treatments. Just because you are expecting does not mean your beauty routine needs to go out the window. Simply apply some caution, moderation and common sense.