The sun emits UV radiation that comes with both risks and benefits. An estimated 90% of our vitamin D comes from the sun. Vitamin D is critical when you are pregnant for both you and your baby. During pregnancy, you may experience some changes to your skin that can make you more sensitive to the sun. Too much sun can damage your skin, increase your risks for skin cancers, and accelerate the effects of aging. Get tips for sun safety so you can maximize the benefits of sunshine while minimizing the damaging effects of the sun. Plus, this article covers how to choose the right sunscreen, sun exposure for your baby, tanning beds, and sunless tanners.
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Some of the light emitted by the sun is ultraviolet (UV) light that is 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% is UVB. If you are indoors, UVB rays do not penetrate through glass. You have to get outside in direct sunlight for UVB rays and make vitamin D. UVA rays go through glass and contribute to skin damage and premature aging.
The UV Index is a measure of 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 your 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 levels of vitamin D, can positively affect your mood. Plus, it is always good to get outside and get fresh air.
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.
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 out in the sun. While there are some risks associated with sun exposure, there is also a benefit to enjoying the sunshine.
It is estimated that 90% of our vitamin D comes from the sun. Vitamin D is sometimes referred to as a hormone because the activated forms of it are hormones. Vitamin D synthesis is a complex process. A simplified summary 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, so it is dissolved in fat and stored in fatty tissue, so your body can store it and use it as needed.
Some of the essential things vitamin D does is help with the absorption of other vital nutrients like calcium, iron, magnesium, phosphate, and zinc. It also regulates immune function, cell growth, and neuromuscular function. During pregnancy, you need vitamin D to help deliver calcium to your baby for their developing bones.
Getting 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, 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 the winter months. This is about if you cut California in half at San Francisco and went across the northern borders of Arizona, New Mexico, Texas, and Philadelphia on the east coast.
Vitamin D During Pregnancy
There is a lot of research backing up the need for adequate vitamin D during pregnancy. A study that examined vitamin D deficiency during pregnancy found 97% percent of Blacks, 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 looked at 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.
The good news is that you cannot get too much vitamin D from the sun. More information on dietary sources, supplementing, and recommended amounts are in this episode.
Vitamin D and COVID-19
There is evidence that vitamin D deficiency may increase risks for COVID-19. As more studies looking at this are published, the evidence has been more mixed. For a summary of some of the research, see this article from JAMA. There are more clinical trials underway. We do know that vitamin D plays a role in immune function. Even if it is not protective against COVID-19, the downside of ensuring you are getting adequate vitamin D outweighs the risk. As with any supplement, please run it by your doctor or midwife.
How Your Skin Changes in Pregnancy
During pregnancy, some changes in your skin could be exacerbated by sun exposure. Some women find their skin more sensitive during pregnancy, making them more sensitive to sun exposure. Stretch marks may become more noticeable with exposure to the sun. If you experience melasma or the mask of pregnancy, when you get dark patches on your face, those can get darker with sun exposure. For more in-depth information on skin issues, you may experience during pregnancy, see this episode.
If you are spending time in the sun in hot weather, you should be taking 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. A meta-analysis of 15 studies found maternal hyperthermia in early pregnancy is associated with an increased risk for neural tube defects. For this reason, fevers during pregnancy can be stressful, and there is more information on that topic in this episode. Heat exposure differs from a fever. As long as you can cool down and you are not overheating, you and your baby should be fine.
Higher temperatures mean you have to pay more attention to your comfort and make sure 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. For more information on heat exposure, including working out, hot yoga, hot tubs, and saunas see this episode.
Several processes happen when you expose 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 to 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, and 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 production of melanin. 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 darkening of your skin reflects some damage, even if you do not get sunburned.
I could not track down any research relating to sunburns during pregnancy. A mild sunburn only affects your skin, and that doesn’t harm your baby. A severe sunburn with side effects like blisters or fever is more serious and is also known as sun poisoning. Blisters have the possibility of getting infected, which wouldn’t be ideal. Fevers are also something you want to avoid during pregnancy, if possible. If you run a fever, you can always call your doctor or midwife and run it by them. If you are thinking of taking anything to reduce your fever, please talk to your doctor or midwife first. You can put a cool washcloth on your forehead or take a cool bath to try and reduce fever. For more information on fevers during pregnancy, see this episode.
You also want to take care of your skin after a sunburn. Aloe is excellent for sunburns. Not the blue or green stuff, just plan aloe vera that should be a clear gel. You can also use aloe if you make postpartum healing pads (padsicles).
Sunscreen is not the only way to protect your skin. You can wear a hat to keep the sun off your face, or wear clothing to protect your skin, or spend time in the shade. If you have exposed skin, you should be using 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, the 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 patch of skin, 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.
Sunscreen SPF only pertains to UVB. You want a broad-spectrum sunscreen for protection against UVA. 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.
If you have any concerns about chemicals in sunscreens, the Environmental Working Group Skin Deep website is an excellent resource. They rate skin products based on the safety of their ingredients. For more information on skincare ingredients to avoid during pregnancy, see this episode. An easy rule of thumb to cut out a lot of chemicals is to opt for fragrance-free products.
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. Tanning beds are not safer than the sun. The World Health Organization’s International Agency for Research on Cancer has labeled tanning beds as 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 (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.
If you are concerned about chemical exposure, the Environmental Working Group’s website Skin Deep is a great resource. 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 patch of skin first, even if you have used this particular product in the past, 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 of their life. 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. For babies under six months, the AAP recommends sunscreen on small areas of the body, 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.
Your baby is born with stores of vitamin D from you. By approximately eight weeks of age, infants deplete the vitamin D stores from birth. Breastmilk is naturally low in vitamin D. Manufacturers of infant formula fortify their products with vitamin D. A small study on breastfeeding mothers found that a maternal intake of 4000 IU/d could achieve substantial progress toward improving both maternal and neonatal nutritional vitamin D status. Supplementing with higher doses of vitamin D will increase the vitamin D in your breastmilk. As always, run any supplements by your doctor or midwife. Talk to your pediatrician for any questions about using sunscreen or having your baby out in the sun.
Tips for Sun Safety
Wear any swimwear that is comfortable and that you feel good wearing. 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. If you are comfortable in a tiny two-piece, please wear it confidently.
You should be using at least SPF 30 and a broad-spectrum sunscreen. You should apply it 15 minutes before going outdoors. It is easy to forget or miss spots like the tops of your feet and your ears. You need to reapply all sunscreen, regardless of SPF, every two hours or after going in the water or sweating. Use a liberal amount, and you need about one ounce (a shot glass full) to cover your whole body. To prevent signs of aging, dermatologists recommend applying an SPF to your face every single day. This stands even if you are planning to be indoors since UVA rays penetrate through glass.
In warm weather, you also want to make sure you stay hydrated. Drinking plenty of water is one of the easiest ways to improve the health of you and your baby. Make drinking water a priority, and make it easy. Take a water bottle along with you when you go out. I love my Hydroflask, and I take it everywhere with me.
Thank you to the amazing companies that have supported this episode.
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