The sun emits UV radiation which comes with both evidence-based benefits and risks. On a positive note, UVB light allows your body to make vitamin D. The downside of UV light exposure is that it damages the DNA in your skin cells, increasing your risks for skin cancers and accelerating the effects of aging. During pregnancy, some changes to your skin create additional considerations for sun exposure. This episode/article has tips for sun safety so you can maximize the benefits of sunshine while minimizing the damaging effects of the sun. Plus, information on choosing a pregnancy-safe sunscreen, tanning beds, sunless tanners, and sun exposure for your baby.
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Some of the light emitted by the sun is ultraviolet (UV) light, a type of electromagnetic radiation. The Earth’s atmosphere filters out a lot of UV, including all UVC light. The UV light that reaches the Earth’s surface is about 95% UVA and 5% UVB. If you are indoors, UVB rays, required to make vitamin D, do not penetrate through glass. Indoors you can still be exposed through windows to UVA rays which contribute to skin damage and premature aging.
The UV Index measures the level of UV radiation ranging from 0 to 11+. The higher the UV index, the stronger your UV exposure. The highest levels of UV light occur from 10:00 am to 2:00 pm. Spending one hour outside at 9:00 am will expose you to the same amount of UV light you would get in 15 minutes at 1:00 pm. Avoiding the peak hours around solar noon will reduce exposure to UV light.
UV light tends to be higher in summer months, near the equator, at higher altitudes, and on clear days. Factors such as reflective surfaces like snow or water can also increase exposure, even in the shade. You can find the UV index for your area in most weather apps.
Enjoy the Sunshine
As the weather warms up in the Northern Hemisphere, I encourage you to get out and enjoy some sun. A review found that exposure to UV radiation in the first three months of pregnancy had beneficial effects on fetal growth and blood pressure during the pregnancy period. Sunlight will increase your vitamin D levels and positively affect your mood. We also know from an episode on how blue light affects your pregnancy that being outside in sunlight at three critical times during the day (sunrise, solar noon, and sunset) will help set your circadian rhythms. There are many benefits to getting outside and enjoying the sun.
Approximately 90% of our vitamin D comes from the sun. Vitamin D is sometimes referred to as a hormone because its activated forms are hormones. A simplified summary of vitamin D synthesis is that when UVB rays hit the surface of your skin, your body uses photosynthesis to start processing it. It is then transported and processed by your liver and kidneys. D is a fat-soluble vitamin that dissolves in fat and is stored in fatty tissue. This allows you to keep it and use it as needed.
Vitamin D is essential and helps with the absorption of other vital nutrients like calcium, iron, magnesium, phosphate, and zinc. It also regulates immune function, cell growth, and neuromuscular function.
Vitamin D During Pregnancy
In addition to your need for vitamin D, during pregnancy, you need vitamin D to help deliver calcium to your baby for their developing bones. A lot of research supports the need for adequate vitamin D during pregnancy. A study that examined vitamin D deficiency during pregnancy found that ninety-seven percent of African-Americans, 81% of Hispanics, and 67% of Caucasians were deficient. Research identifies vitamin D deficiency as a risk factor for preeclampsia. Evidence also links vitamin D deficiency with increased odds of primary cesarean section. Another study examined how maternal vitamin D deficiency could affect a baby later in life. A deficiency was associated with impaired lung development in 6-year-olds, neurocognitive difficulties at age 10, increased risk of eating disorders in adolescence, and lower peak bone mass at 20 years.
Vitamin D from the Sun
The amount of vitamin D you get from the sun varies depending on where you live, the time of year, the time of day, how much skin is exposed, your skin, etc. If you live near the equator, you are receiving more sunlight. If you live above 37 degrees latitude in the US, you probably aren’t getting enough vitamin D from sunlight in winter. This is about if you cut California in half at San Francisco and crossed the northern borders of Arizona, New Mexico, Texas, to Philadelphia on the east coast. The good news is that you cannot get too much vitamin D from the sun. See this episode for in-depth information on vitamin D, including recommended amounts, dietary sources, and supplements.
Several processes happen when you expose your skin to UV light. On a positive note, UVB light allows your body to make vitamin D. The downside of UV light exposure is that it damages the DNA in your skin cells. This can cause skin cancer, premature signs of aging, wrinkles, leathery skin, or spots. We are diurnal animals that will always have some level of exposure to sunlight. Thankfully we have some natural protection from damage produced by UV rays in the form of melanin.
Melanin is a natural pigment responsible for the color of your skin. Your melanin levels are primarily due to genetics; the more melanin you produce, the darker your skin. Melanin also absorbs UV light and protects your cells against damage. Plus, when your skin is damaged by UV light, your melanocytes increase your melanin production. This is what creates a tan. It would be fantastic if this cycle of UV light exposure and melanin production worked in perfect harmony. Unfortunately, there is no such thing as a safe tan. Any skin darkening reflects some damage, even if you do not get sunburned.
Sun Exposure During Pregnancy
You have some additional considerations for sun exposure during pregnancy. Your baby is protected from the sun’s rays in the womb. By week 18, your baby gets better at detecting light and dark, so they should see a glow when you are in the sun. While your baby is protected, many hormonal changes in pregnancy can affect your skin and your sensitivity to the sun.
Many expecting moms find that their skin is more sensitive during pregnancy. Skin sensitivity presents as redness, swelling, tenderness, or irritation in response to products, fabrics, or sun exposure.
Stretch marks are off-color lines that can appear on your breasts, belly, butt, and thighs. Stretch marks happen when the underlying supporting tissue stretches and tears during rapid stretching of your skin. These lines can be pink or reddish and fade to a lighter color than your skin tone. The good news is that stretch marks fade and become less noticeable over time. The bad news is that stretch marks may become more prominent with exposure to the sun. Stretch marks do not have the same melanin content as the surrounding skin. After sun exposure, the surrounding skin may tan, but your stretch marks will not, making them more noticeable.
Melasma is a common skin condition during pregnancy and presents as darker patches of skin on your forehead, cheeks, nose, or upper lip. During pregnancy, an increase in estrogen can increase your production of melanin. There is no way to prevent melasma, but you can limit your sun exposure which tends to darken these spots.
See this episode for more in-depth information on skin issues you may experience during pregnancy.
Another consideration for sun exposure during pregnancy is heat exposure. If you are in the sun in hot weather, you should take precautions to avoid overheating, which can cause hyperthermia. During pregnancy, there is the concern of an elevated core temperature causing neural tube defects, spontaneous abortion, and other abnormalities. Higher temperatures mean you have to pay more attention to ensure you are not getting overheated. This isn’t just a theoretical risk. Research has shown that hot weather and exposure to high temperatures can increase the risks of stillbirth. Another study linked higher temperatures to lower birth weights. A meta-analysis of 15 studies found that maternal hyperthermia in early pregnancy is associated with an increased risk for neural tube defects.
You may want to spend more time indoors with air conditioning and limit your time outside, especially in the sun. If you plan to be out in hot weather for long periods, plan by dressing in cooler clothing and sticking to the shade when possible. You also require more fluids in hot weather, and it is critical to increase your water intake to stay hydrated. You and your baby should be fine as long as you can cool down and you are not overheating. See this episode for more in-depth information on heat exposure, including working out, hot yoga, hot tubs, and saunas.
Sunburn and Sun Poisoning
I could not track down any research relating to sunburns during pregnancy. A mild sunburn only affects your skin and doesn’t harm your baby.
A severe sunburn with side effects like blisters or fever is more serious and is classified as sun poisoning. Blisters have the possibility of getting infected. Studies have linked maternal fevers in pregnancy to complications like autism, neural tube defects, oral clefts, and congenital heart defects. If you have a fever, you should contact your doctor or midwife. You can take measures to cool off, like running a washcloth under cool water and putting that on your forehead or taking a tepid bath or shower. You should be wearing light cool clothing, and don’t bury yourself under a ton of blankets. It has become very common to take over-the-counter medicine to reduce a fever. Before taking any medication, even if it is available over the counter, you need to run it by your doctor or midwife. For more information on fevers during pregnancy and the safety of fever-reducing medications, see this episode.
If you get a sunburn, aloe vera is an excellent product to apply to your skin. Not the blue or green stuff, just plain aloe vera that should be a clear gel. You can also use aloe if you make postpartum healing pads (padsicles).
Protecting Your Skin from Sun Exposure
You can wear a hat to keep the sun off your face, wear clothing to protect your skin, or spend time in the shade. You should be more mindful when the UV index is high, particularly between 10:00-2:00. If you have exposed skin, use sunscreen.
There are two types of sunscreen; chemical sunscreens absorb the sun’s rays, and physical sunscreens stay on the surface of your skin and deflect rays. Claims on sunscreen labels, like water-resistant, SPF, or broad-spectrum, are governed by FDA requirements.
SPF stands for sun protection factor. SPF measures how much UV radiation is required to produce a sunburn on protected skin compared to skin without sunscreen. Scientists determine SPF in a laboratory by applying sunscreen to a small skin patch, exposing it to UV light, and measuring how long it takes for the skin to turn pink. It is a common misconception that an SPF rating tells you how long you can stay in the sun without getting burned. The goal of regulating SPF measurements is to allow you to compare two different sunscreens. An SPF of 30 is stronger than an SPF of 15. Both should be reapplied every two hours or after going in the water or sweating. The American Academy of Dermatology recommends an SPF of a least 30, which blocks 97% of UVB rays. No sunscreen can block 100%. You could get a higher SPF, but 30 should be sufficient.
Sunscreen SPF only pertains to UVB. You want a broad-spectrum sunscreen for protection against UVA. This is especially important because UVA rays contribute to skin damage and premature aging.
There has been much controversy over the safety of ingredients used in sunscreen. A few years ago, Johnson and Johnson voluntarily recalled sunscreens due to contamination with benzene, a chemical that causes cancer. This happened after an independent third-party tested 294 products and found benzene in 78.
Chemical sunscreen is absorbed better by your skin than physical sunscreen, which tends to stay on the surface of your skin. There is evidence to show that the active ingredients in sunscreens, like oxybenzone, are absorbed. In a systematic review of 29 studies, researchers did not find sufficient evidence to support a causal relationship between oxybenzone and adverse health outcomes. With the scrutiny on safe skincare and sunscreens, we will hopefully see more data in the future.
If you have any concerns about chemicals in sunscreens, the Environmental Working Group Skin Deep website offers a free guide for sunscreen. The EWG recommends avoiding products with oxybenzone, vitamin A (retinol palmitate), added insect repellant, and sprays and powders. Using a fragrance-free lotion is the simplest way to cut back on some chemicals. For more information on pregnancy-safe skincare and ingredients to avoid, see this episode.
Tanning beds are not safer than the sun. Like the sun, tanning beds emit ultraviolet (UV) light. These devices emit mainly UVA light. This means tanning beds will not significantly affect your vitamin D levels but will contribute to skin damage and premature aging. The World Health Organization’s International Agency for Research on Cancer has labeled tanning beds carcinogenic. The WHO has an in-depth report outlining the risks of tanning beds with suggestions for reducing those risks ranging from better educational campaigns to banning them entirely. Tanning beds are one of the most dangerous ways to get tan.
As more data has come out about the harmful effects of exposure to UV light, sunless tanners have increased in popularity. The active ingredient in these is dihydroxyacetone, abbreviated DHA, also known as glycerone. (Not to be confused with DHA as in the Omega 3.) Dihydroxyacetone is from plant sources like sugar beets and sugar cane. When applied to your skin, it causes a chemical reaction with amino acids on the surface of your skin and has a darkening effect. This is thought to affect the outermost cells of your skin. The consensus is that this ingredient is generally recognized as safe when used topically, even during pregnancy.
Even if dihydroxyacetone, the active ingredient, is deemed safe, there could be other ingredients you may want to avoid in a product. You should also try a test skin patch first, even if you have used a particular product, since your skin may be more sensitive during pregnancy.
Sun Exposure and Your Baby
The American Academy of Pediatrics recommends keeping your baby out of direct sunlight for the first six months. This does not mean that sunshine can never shine on your infant. If your baby is outside, they should have a hat and clothing to cover the skin or be mainly in the shade. The AAP recommends sunscreen for babies under six months on small body areas, such as the face. After six months, you should apply sunscreen to their body. If your baby is younger than one year old and gets sunburned, contact your pediatrician. Talk to your pediatrician for any questions about sunscreen or having your baby in the sun.
Your baby is born with stores of vitamin D from you. Infants deplete their vitamin D stores from birth by approximately eight weeks of age. Breastmilk is naturally low in vitamin D, and infant formula manufacturers fortify their products with vitamin D. Supplementing with higher doses of vitamin D will increase the vitamin D in your breastmilk. A small study on breastfeeding mothers found that a maternal intake of 4000 IU/d could substantially improve maternal and neonatal nutritional vitamin D status. As always, run any supplements by your doctor or midwife.
Tips for Sun Safety
You should enjoy the sun. A few tips can help you stay safe from too much sun exposure.
Maternity swimwear is usually one-piece or two pieces with a tank top to cover your belly. You do not have to hide your belly when you are pregnant. Two-piece swimsuits are great because they will fit no matter how big your belly gets. Wear any swimwear that is comfortable and that you feel good wearing. If you are comfortable in a tiny two-piece, please wear it confidently.
You should apply broad-spectrum sunscreen with at least SPF 30 15 minutes before going outdoors. It is easy to forget or miss spots like the tops of your feet and ears. Use a liberal amount; you need about one ounce (a shot glass full) to cover your whole body. Regardless of SPF, you need to reapply all sunscreen every two hours or after going in the water or sweating. To prevent signs of aging, dermatologists recommend applying an SPF to your face daily. This recommendation stands even if you plan to be indoors since UVA rays penetrate through glass.
In warm weather, it is critical to stay hydrated. Staying hydrated is crucial to help your overall health. You have increased water requirements when pregnant and eliminate more water in hot weather. Make drinking water a priority and easy by always having a water bottle with you.
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