The skin of pregnant women is subject to particular hormonal variations and may react in an unusual fashion.
Therefore, it is important for all skin types to avoid sun burn.
UV rays increase the risk of onset and aggravate the notorious melisma (or chloasma) – pregnancy mask (localized brown stains which appear in the second trimester of pregnancy on the forehead, cheekbones, nose, chin and around the mouth. Whether due to hyperpigmentation of the skin or to hormones, only a wide-brimmed sun hat offers protection against pregnancy masks.
Also avoid exposing your legs to the sun, as UV rays and heat cause the dilation of blood vessels and encourage the development of varicose veins.
Use very high protection sun cream.
As a general rule, favour shady areas. If you decide to go out in the sun yourself, drink more water than usual.
Also consider protecting your eyes with sunglasses produced to European standards of UV protection. Pregnant women produce less tears which weakens their eyes. To avoid irritation, headaches, conjunctivitis and other discomfort, the use of high protection sunglasses is strongly recommended.
To summarize, when faced with so many risks and discomforts, you are almost certainly better off keeping to the shade during your pregnancy.