I live in the great Northwest, and as beautiful as it is, it also comes with fairly long, chilly winters meaning less frequent sun exposure to my skin. Considering the majority of my pregnancy has taken place through these winter months, I have made a conscious effort to get enough Vitamin D. Also known as the "Sunshine Vitamin,” your body converts sunlight into vitamin D after it hits unprotected skin.
Why is Vitamin D Important During Pregnancy?
Because vitamin D supports normal fetal growth during pregnancy, including bone, neurologic, and immune system development. Other research suggests if a woman has low vitamin D levels during pregnancy, her baby may have an increased risk of getting eczema through the first year of life (1). A relationship between vitamin D and eczema has been established in the non-pregnancy population too.
Also, low maternal vitamin D levels (<40 ng/mL) during pregnancy may be associated with an increased risk of preeclampsia, gestational diabetes mellitus, infection, preterm birth and a baby born small-for-gestational age (2).
Vitamin D also increases calcium absorption, which is another important nutrient during pregnancy.
Here are some tips to ensure you and your baby are receiving adequate amounts of vitamin D.
Are you at risk for vitamin D deficiency?
Women at risk are those who follow a vegetarian or vegan diet, have darker pigmented skin, have limited sun exposure, and a body mass index >30 (3).
Vitamin D Recommendations
The recommendation for Vitamin D supplementation during pregnancy is controversial and varies depending on what source you’re reading. This makes it very difficult to know how much vitamin D is necessary to support a healthy body. Best bet is to talk to your doctor.
Here are vitamin D recommendations from a few health agencies willing to even commit to providing a number, and as you can see, the recommendations are extremely different!
- Institute of Medicine, Food and Nutrition Board: 600 IU for everyone up to age 70 (4)
- Vitamin D Council: 6,000 IU for pregnant and lactating women (5)
- GrassrootsHealth: 4,000 IU for pregnant women after 12 weeks gestation (6)
How Should I Take My Vitamin D?
Vitamin D is effective when taken any time of the day, with or without food. It's preferred to take your vitamin D on a daily basis rather than a huge amount once per week, especially if breastfeeding. This avoids large peaks, followed by low levels, when your baby drinks breastmilk.
Mixing Sun Exposure and Vitamin D Supplementation
If you’re lucky enough to live in a sunny place, it is okay to use both sun exposure and intermittent supplementation to receive your vitamin D. The solution: simply do not take your vitamin D supplement on the days when you receive adequate sun exposure. Studies suggest 5–30 minutes of sun exposure midday, at least twice a week to the face, arms, legs, or back without sunscreen usually lead to sufficient vitamin D levels for most people (4).
If you live north of the 37th parallel, the skin makes very little vitamin D from the sun, except during the summer months, so taking a vitamin D supplement is important. People who live in these areas are at relatively greater risk for vitamin D deficiency.
What Type of Vitamin D Do I Take?
Vitamin D3—the label will say cholecalciferol, which is the most bioavailable form of vitamin D and is equivalent to the vitamin D formed in our skin from ultraviolet B light.
Don’t Rely On Prenatal Vitamins For Vitamin D
According to Mayo Clinic, most prenatal vitamins do not include optimal amounts of vitamin D. Talk to your doctor about other sources of vitamin D to boost your levels.
Bottom Line: Further studies are required to determine the optimal dose of vitamin D supplementation during pregnancy. For now, ensure you’re getting at least the minimum daily recommendation of 600 IU. Be sure to talk to your healthcare provider before taking any supplements.
In Health and Happiness,
Kelly Harrington, MS, RDN
Registered Dietitian Nutritionist for Healthy Goods
1. Jones AP, Palmer D, Zhang G, Prescott SL. Cord blood 25-hydroxyvitamin D3 and allergic disease during infancy. Pediatrics. 2012 Nov;130(5):e1128-35.
2. Wei SQ, Qi HP, Luo ZC, Fraser WD. Maternal Vitamin D Status and Adverse Pregnancy Outcomes: A Systematic Review and Meta-Analysis. J Matern Fetal Neonatal Med. 2013 Jan 13.
3. Dietary Supplement Fact Sheet: Vitamin D. Office of Dietary Supplements.
4. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press, 2010.
5. Vitamin D Supplementation. Vitamin D Council.
6. Hollis BW, Johnson D, Hulsey T, et al. Vitamin D Supplementation During Pregnancy: Double-Blind, Randomized Clinical Trial of Safety and Effectiveness. J of Bone and Mineral Research. Vol 26, No. 10, Oct. 2011:2341-2357. www.grassrootshealth.net