Sun During Pregnancy Lowers Baby's MS Risk

by Pregnancy.org Staff

out in the sunYour baby benefits from all the good things you do for yourself during pregnancy -- nutrition, exercise, and a even a healthy amount of sunshine. The sun enriches your body with vitamin D which is transferred to your unborn little one. So long as you don't overdo it, the sun will do you AND your baby a world of good!

Vitamin D levels have previously been linked to multiple sclerosis. Now experts suggest that an expectant mom's lack of sunlight -- the main source of vitamin D -- could predispose her baby to developing MS later in life.

According to an Australian study, low sun exposure during the first three months of pregnancy might result in a higher risk of developing multiple sclerosis later in life. Babies whose first trimester in-the-womb occurred during the winter were at 30% higher risk of developing MS.

Sunshine, Vitamin D and Multiple Sclerosis

What we know:
• MS is a disease of latitudes, with high rates reported in colder climates and lower rates seen in the tropics. The further you live from the equator, the higher your risk of developing MS.

• Low levels of vitamin D during pregnancy -- either because of inadequate nutrition or exposure to the sun -- have been associated in several studies with increased risk of adult multiple sclerosis.

What's uncertain:
• Sunlight exposes the body to both ultraviolet A (UVA) and ultraviolet B (UVB) rays. Vitamin D production increases mainly with exposure to UVB. Researchers are uncertain whether UVA rays might offer some of the protection against MS.

If You're Pregnant or Trying to Conceive

Before pregnancy: Try for an adequate vitamin D levels before pregnancy. If you're first appointment is between 8 and 12 weeks, you've missed the window of opportunity to treat a first trimester vitamin D deficit.

During pregnancy: Get plenty of sunshine and vitamin D during pregnancy. Sun exposure lowers the risk of MS, but your baby benefits from vitamin D in more ways. Newborns whose first trimester gestating was in the summer weigh more at birth. What about later in pregnancy? Adequate vitamin D or sunshine in third trimester helps your baby form strong bones and muscles and lower the chance of immune disorders.

Baby benefits: Vitamin D protects your baby during the newborn period. High levels of vitamin D at birth protect against wheezing and respiratory infections, including RSV and bronchitis.

Vitamin D Sources

Your body can make its own vitamin D with help from the sun. Other ways to meet your "sunshine vitamin" requirement include natural food sources, fortified foods and supplements.

Fun in the sun
Fair skinned people make enough vitamin D from having their hands, arms and face in the summer sun for a few minutes each day during normal, day to day outdoor activities. People with medium skin need more sunlight and those with darker skin need three to six times as much sunlight as fair skinned people.

Light skin -- 15-20 minutes daily
Medium Skin -- 25-30 minutes daily
Dark Skin -- 40-45 minutes daily

The farther north you live, the longer you'll need to spend outdoors in the winter. For example, fair skinned women living in Victoria, BC would need to spend two to three hours a week out in the sun.

Supplements:
If natural sunlight is unavailable, you can supplement. Guiulio Disanto, MD, of the University of Oxford, England, says, "The growing body of evidence linking low sun exposure and MS risk was enough to warrant vitamin D supplementation during pregnancy." He suggested that up to 4,000 IU/day would be suitable -- 10 times the current USDA-recommended intake. Dr. Disanto's suggested intake does fall within the tolerable upper intake levels as outlined by the Institute of Medicine, Food and Nutrition Board.

Good food sources:

  • Fatty fish like salmon, mackerel and tuna (3 ounces wild caught salmon contains 420 IU)
  • Sardines (1 can has 250 IU)
  • Shitake mushroomos (45 IU per serving)
  • Beef liver
  • Eggs (each yolk has 20 IU)

Fortified food sources:

  • Milk, yogurt, cheese (1 cup skim and lowfat milk contains 100 IU)
  • Some orange juice
  • Ready-to-eat cereal (1 cup of most cereals has 40 IU)

Special risk groups:

  • Darker-skinned women who move to regions with low ambient RV radiation like the Pacific Northwest or United Kingdom
  • Women who have very indoor lifestyles (indoor jobs, indoor leisure time)
  • People with fat malabsortion, caused by a variety of medical conditions including some forms of liver disease, cystic fibrosis, and Crohn's disease 
  • Women with BMI over 30
  • Women who have had a gastric bypass surgery

Are you at high risk for vitamin D deficiency?

About the study: Disanto G, et al "Gestational ultraviolet and vitamin D exposure and the risk of multiple sclerosis in the United Kingdom" AAN 2011; Abstract P05.289. Researchers combed birth records of over 1500 MS patients born between 1920 and 1950. They discovered that fewer MS patients were born to moms whose first trimester occurred during summer months and more were born to moms whose first trimester occurred during during winter months. Weaknesses: The study looked at ambient ultraviolet radiation by mother during pregnancy and didn't consider dietary intake.

Sources: National Institutes of Health, Office of Dietary Supplements. Dietary supplement fact sheet: Vitamin D.

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