Vitamin D during pregnancy: key points to know

Medically reviewed by Rosanna Sutherby, PharmD on September 21, 2020. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.


Getting enough of the right nutrients is vital for good health during pregnancy—for both yourself and your baby. One key nutrient to keep in mind is vitamin D, also known as the "sunshine vitamin." Read on to find answers to questions you might have about vitamin D during pregnancy—including how you can get vitamin D, recommended vitamin D intake levels, symptoms of deficiency, and more.

Where do you get vitamin D?

Before we dive into the benefits and risks of vitamin D during pregnancy, let’s discuss how you get vitamin D in the first place.

Exposure to sunlight

Vitamin D is produced when rays from the sun land on your skin. Several factors are at play when it comes to vitamin D production and sunlight exposure. Age is one of them, for example: as we age, our skin isn’t able to produce as much vitamin D. Skin pigmentation is another, as people with darker skin need a greater amount of sunlight to generate vitamin D (this is due to the properties of melanin, which absorbs energy from the sun’s rays so there’s less of it to trigger vitamin D production). Other factors include seasonality and whether you regularly wear sunscreen when you spend time outside.

Eating the right food

Vitamin D doesn’t occur naturally in too many foods. But you can find this vitamin in fatty fish like mackerel, salmon, and tuna. It can also be found in egg yolks, cheese, beef liver, and foods that are fortified with vitamin D—such as many kinds of cereal, dairy products, and orange juice.

Because getting enough vitamin D during pregnancy can be difficult from food and sunlight alone, many people turn to supplements.

Taking vitamin D supplements

Vitamin D can be found in supplements in two different forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Both of these forms can increase your vitamin D level.

Benefits of vitamin D during pregnancy

Getting enough vitamin D is important for anyone, but it’s especially key for expecting mothers. Getting sufficient vitamin D helps promote healthy development of the baby and is beneficial for overall health throughout pregnancy.

During pregnancy, vitamin D supports your immune system and the health of your bones, muscles, and teeth. It’s also necessary for absorbing calcium and phosphorus. For the developing baby, vitamin D supports healthy bone development. Adequate vitamin D may also help prevent preterm birth.

Low levels of vitamin D and preeclampsia

A deficiency in vitamin D during pregnancy is associated with preeclampsia, which is a condition that only occurs during pregnancy. Symptoms can begin after week 20 of pregnancy and may include protein in the urine, high blood pressure, and water retention. In cases of severe preeclampsia, you may experience headaches, blurred vision, inability to tolerate bright light, fatigue, nausea and/or vomiting, pain in your upper right abdomen, shortness of breath, and a tendency to bruise. Preeclampsia affects roughly 5-8% of pregnancies—though keep in mind that these symptoms can be caused by other health issues, as well.

Preeclampsia can also affect the arteries that carry blood to your placenta. When the placenta doesn’t carry enough blood, your baby may not get enough nutrients, oxygen, or blood, which can lead to low birth weight or preterm birth.

Symptoms of vitamin D deficiency

A deficiency in vitamin D can result in a number of different signs and symptoms, including:

  • Fatigue or feeling tired
  • Joint pain
  • Depression
  • Muscle pain
  • Weakness
  • Thinning hair

Of course, these can be normal pregnancy-related symptoms as well, so it’s always good to check in with your healthcare provider if you’re experiencing any of these.

What causes low vitamin D levels?

Vitamin D deficiency is quite common in the United States and throughout the rest of the world. There are several reasons for this. First off, there aren’t many foods that naturally contain vitamin D, so it isn’t always easy to get from one’s diet. Second, many people spend a lot of time indoors, where there’s no sunlight to trigger vitamin D production in the skin. In general, then, low vitamin D is typically caused by inadequate dietary intake and a lack of exposure to sunlight.

How much vitamin D to take during pregnancy

Wondering how much vitamin D you need? According to the National Institutes of Health, the recommended dietary allowance (RDA) of vitamin D during pregnancy is 600 IU/day, with a tolerable upper intake level of 4,000 IU/day. (The amount of vitamin D in foods and supplements is usually expressed in terms of International Units (IU), so “IU/day” refers to “International Units per day.” The tolerable upper intake level refers to the highest amount of a nutrient that can be taken without the risk of adverse effects on health.)

How can you measure your vitamin D intake in International Units (IU)?

If you’re taking a vitamin D supplement, the amount of vitamin D will likely be listed on the supplement's nutritional label, either in International Units or micrograms (2.5 micrograms = 100 IU). Micrograms may be abbreviated as "mcg."

Vitamin D amounts aren’t always listed directly on the labels of food items. However, labels often do list the percent Daily Value (DV), which reflects the amount of vitamin D in a serving of that food as a percentage of 800 IU.

Finally, you can also get a sense of the vitamin D content of various kinds of food by visiting the National Institutes of Health's resource on vitamin D (see Table 3).

Risks of too much vitamin D intake during pregnancy

When taking vitamin D during pregnancy, be aware that excessive supplementation can occur with vitamin D, leading to toxicity. Hypercalcemia refers to a buildup of calcium in the blood and can happen to the fetus when too much vitamin D is ingested. The highest daily dose in pregnancy is 4,000 IU/day, as mentioned above. In the third trimester, a higher dose may be recommended by a healthcare provider for a short period of time, though this is done under observation while monitoring calcium levels.

Signs of vitamin D toxicity

In addition to calcium buildup, signs of too much vitamin D can include:

  • Nausea
  • Vomiting
  • Weakness
  • Headache
  • Frequent urination
  • Painful muscles
  • Kidney damage and kidney stones
  • High blood pressure

Also referred to as hypervitaminosis D, the risk of vitamin D toxicity is rare. Typically, it occurs as a result of excess vitamin D supplementation (as opposed to too much sun exposure or high intake due to one’s diet).

Vitamin D after birth

After your baby is born, they’ll likely need a vitamin D supplement (human milk does not, by itself, typically provide enough vitamin D for a baby). Vitamin D is important for babies, as too little can lead to an increased risk of rickets, which is a softening or weakening of the bones. Sun exposure isn’t recommended for babies, so supplements help prevent a deficiency. It’s best to speak with your healthcare provider to learn how much vitamin D your baby needs through supplementation.

Testing your vitamin D levels

You can easily check your vitamin D levels—from the convenience and privacy of home—with a vitamin D test kit from Everlywell. To take the Everlywell at-home Vitamin D Test, you just collect a small sample of blood (with a simple finger prick) and ship it to the lab using the prepaid shipping label included with the kit. You’ll view your results on our secure, online platform—and can easily share them with your healthcare provider to learn if they have any recommendations for you.


When should you take vitamin D supplements?


References

1. Vitamin D. National Institutes of Health. URL. Accessed September 21, 2020.

2. Title. Publication. URL. Accessed September 21, 2020.

3. Vitamin D and Pregnancy. American Pregnancy Association. URL. Accessed September 21, 2020.

4. Preeclampsia. American Pregnancy Association.URL. Accessed September 21, 2020.

5. Preeclampsia. Mayo Clinic. URL. Accessed September 21, 2020.

6. Sizar O, Khare S, Goyal A, et al. Vitamin D Deficiency. [Updated 2020 Jul 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532266/

7. Larqué E, Morales E, Leis R, Blanco-Carnero J, E: Maternal and Foetal Health Implications of Vitamin D Status during Pregnancy. Ann Nutr Metab 2018;72:179-192. doi: 10.1159/000487370

8. Nutrition and healthy eating. Mayo Clinic. URL. Accessed September 21, 2020.

9. Does my baby need a vitamin supplement? Mayo Clinic. URL. Accessed September 21, 2020.

10. Vitamin D supplementation during pregnancy. World Health Organization URL. Accessed September 21, 2020.

11. Calcium and Vitamin D. National Osteoporosis Foundation. URL. Accessed September 21, 2020.

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