If you are reading this article then you or someone you know is probably pregnant. Congratulations! You may also be reading this article because you are confused about what vitamin D supplements you should be taking, the safety, and amount to keep you and your baby healthy. It’s amazing how once we are in charge of someone else’s well-being we become our own private investigators!  I am glad you found your way to this page, because what I am about to share is very important. (If you are just looking for Vitamin D information on a non-pregnant adult, check out this article)

sun belly

Stats and why you should care

With approximately 10% of women in the US currently pregnant, and 360,000 births per day ¹, supporting this population with proper nutrients is essential for both a healthy mom and a healthy baby. The shocking part is, evidence suggests that as many as 20-40% of pregnant women are vitamin D deficient ².  That is a large percentage no matter how you look at it, and a dangerous one at that, and here is why: 

  • During pregnancy, low vitamin D has been associated with disordered skeletal homeostasis (the bones are not formed right), rickets, and fractures of the newborn3,4
  • Low vitamin D has been linked to an increase of Infections (like bacterial vaginosis) and inflammation in mom, and an increase in Preterm birth and low birth weight in baby.
  • Birth outcomes have been shown to change, such as an Increased rate of c-sections⁶ 
  • An Increased risk of gestational diabetes in vitamin D deficient moms⁷
  • There are Issues in children as they grow such as decreased motor and social development, higher incidence of acute respiratory infections and recurrent wheezing. Preliminary studies even showed a reduction in autism to children born to mother’s who supplemented during pregnancy.⁸
  • Increased risk of depression both during and after pregnancy, also known as Postpartum Depression (PPD)⁹

These health issues are so diverse because vitamin D is involved in many important processes in the body. 

So what is vitamin D exactly, and what does it to for a pregnant mom and new baby?

Vitamin D is actually a hormone, not a vitamin, that is made during multiple conversion processes in our body. With the help of the sun and cholesterol in our diet, our skin makes pre-vitamin D3, which then goes to the liver and then the kidneys to become the active form of vitamin D our bodies can use for multiple important processes.  We also get it from food (but in only a few sources) and supplementation.

In a pregnant mother, it is thought that her own vitamin D can cross the placenta which has its very own vitamin D receptors and enzymes to then convert it into its active form for baby to use. In fact, we also know that most of our organs and tissues have vitamin D receptors10, and this shows us how important this hormone is to both the mother and babies health.


The most well-known action of vitamin D is keeping the balance between calcium and phosphate in the blood, which in turn helps build healthy bones, contract muscles, keep cells working properly, and our nervous system firing efficiently. This is not only important for mom, but the baby inside her, since her vitamin D is needed for the high demands of optimal growth. 

Also important to pregnancy is the interplay with her immune system to prevent infections and to create a proper maternal immune response to the placenta. Vitamin D also regulates glucose and insulin which can protect from getting gestational diabetes. Last, but definitely not least, is the correlation we see between vitamin D and our mood, specifically depression, or in the post-partum period known as PPD (postpartum depression). Research suggests that women with lower levels of vitamin D are more at risk for depression both during and after pregnancy,and testing levels mid-pregnancy can give insight and be a way to prevent this very difficult diagnoses from happening.11

Signs and symptoms of deficiency 

The best way to know if you are vitamin D deficient is to test (more on that below), but here are some signs and symptoms to look out for:12

  • Skeletal malformations
  • Muscle weakness or bone pain
  • Depression and cognition issues
  • Symptoms of anemia: 
    • Fatigue, Impaired wound healing, dark eye circles, hair loss
  • Getting sick often
  • Lower endurance during exercise

Who is at risk?

So we can see that having optimal vitamin D levels is important, but who is really at risk of having low vitamin D? Doesn’t it have to do with how much sun you are getting? Well, yes and no…let’s dive into who should really be paying attention to their levels.  

In 2011, ACOG (American College of Obstetricians and Gynecologists), and Endocrine Society  released guidelines on the prevention of Vitamin D deficiency and supplementation. They concluded that widespread testing for vitamin D deficiency was not warranted, UNLESS it was in a high-risk group. Here is a list of high risk groups:13,14,15

  • Vegetarians
  • Women who have limited sun exposure. This includes living above the 37 deg in latitude (That is anywhere North of San Francisco, Denver, St Louis, and Richmond) and those who wear protective clothing and sunscreen. 
  • Ethnic minorities, especially those with darker skin
  • Children under 4
  • Obese (BMI >30)
  • On certain medications, such as anticonvulsants and meds to treat AIDS/HIV, glucocorticoids, or antifungals like ketoconazole.
  • Certain chronic diseases such as Nephrotic syndrome, chronic granuloma-forming disorders, some lymphomas, and primary hyperparathyroidism. 
  • Any digestive disorder that could affect absorption, Celiac disease being one example.

Vit D latitude

Do you see yourself in any of these groups? If you are pregnant, you most likely are also included according to the percentages I stated above, especially if it is during the 3 non-summer months of the year.  

*So, to summarize, if you are a pregnant female with one or more risk factors, research supports monitoring blood levels of vitamin D in early and mid-pregnancy.16*

How to know if you are deficient:

Test! It is a simple blood test, 25 (OH) D to be exact, that your provider can run during any routine or scheduled blood draw. An optimal blood level has not yet been determined during pregnancy, but most agree that at least 20 ng/mL (50 nmol/L) is needed to avoid bone issues, but less than 32 ng/ml is considered deficient based on the most widely used labs and research.17 Many speculate that mood and immune system issues are improved at a higher optimal range, but there is not enough research yet to support this clinical observation.

It is very important to monitor your levels both before and after any supplementation. The reason for this is because although many studies have been done to show the safety of taking Vitamin D, it does have toxicity risks due to it being a fat soluble vitamin. What this means is that the body is able to store it in it’s fatty tissue for long periods of time, and release it into the blood when it is needed.  Super handy, but unlike water soluble vitamins (think B-vitamins) the body does not just pee the extra out, but instead stores it, which can lead to a toxic level in the body if taken in too high of amounts. Studies in pregnancy have shown a safe level of 4,000 IU/day 13 and even up to 10,000IU/day for a short period of time (<3 months).14

That being said, always talk with your provider about what amount, if any, of supplementation is right for you. 

How to get Vitamin D

So if you find out you need more vitamin D, what is the best way to get it?  There are three areas to focus on: Diet, sun, and supplements. You can get vitamin D2 through diet in foods such as fatty fish, mushrooms (especially if exposed to UV light!18), egg yolk, and fortified foods. Take a look at the list of high vitamin D foods below for more options.19 

Vit D Image

Sunlight is also a key component to production in the body, but you need to expose your skin without sunscreen for at least 10-15min, 2 to 3 times per week between 10am and 3pm during a non-winter month.20

And remember, if you are north of the 37 parallel, you won’t be getting as much as someone farther south. It can be a balance between skin cancer protection and getting enough for vitamin D synthesis, so be sure to be careful and wear chemical-free sunscreen when out for more than 30min at a time.

The third and most efficient way to get vitamin D is through supplementation.  You can get D2 or D3 through supplements, and I highly recommend getting D3 for a few reasons:

  1. This is the form that is naturally made in our body from sun exposure. 
  2. We have a better affinity for D3 at the receptor level
  3. It is the preferred form during liver conversion.21

My favorite way to get it is in drops emulsified in a fat-soluble oil for better absorption, because this way you can tailor the dosage to meet the needs of an adult or child. It comes in many forms, though, and is found in cod liver oil as well. 

So….how much?

Although there have not been enough studies on pregnant women to determine an exact dosage recommendation, many guidelines have been released that range anywhere from 600IU/day to 2000IU/day.  This is confusing for many because it’s such a wide range, so here are some facts to think about:

  • If you are not deficient, this number will not be as high as someone who is deficient. ACOG says that 600IU (the amount in most prenatals) is efficient for most, but if you are deficient then they recommend up to 2000IU/day.17
  • There are many studies that show 600IU/day is just not cutting it. Deficiency is still happening and some recommendations say to add 1000IU/day to the 600IU already in a prenatal to everyone.15, 21
  • Studies are finding that skin color, race, and genetics DO matter when it comes to our individual needs. Taking prenatal vitamins did not prevent deficiency in 29% of black women and 5% of white women. Insufficiency was 54% and 42% of black and white women, respectively. These percentages were similar for their babies as well. 23, 24
  • Studies have shown levels of 4000IU/day to be safe, and up to 10,000IU/day short term (3 mo) to be safe as well13

In the end, you should always talk with your healthcare provider about the dosage right for you, and don’t forget to include sun exposure and a balanced vitamin D rich diet to the mix as well, choices that will be sure to benefit you in other ways!

Infants and Babies 

So what about the babes!?  This is a little more clear cut, kind of, but it matters if they are breastfed or formula fed. 

Breastfed babies: 

  • The American Academy of Pediatrics recommends that “children who are exclusively breastfed should receive supplementation with 400IU/day of Vitamin D soon after birth and continue to receive during their development up to adolescence”. The IOM also agrees on 400IU/day for children under 1, and 600IU/day for children 1-8 years of age. If the baby was born premature, monitoring of vitamin D levels in the hospital while being supplemented, then continued supplementation after they go home is recommended. 22,25
  • Another way to consider getting enough vitamin D to the child is through the mom! The Institute of Medicine says that if mom takes about 4000-6000IU/day, it will pass on an adequate amount to baby, and this is just fine. 

Formula fed babies:

  • NICE recommends that “all infants and young children aged 6 months to 3 years are advised to take a daily supplement containing vitamin D in the form of vitamin drops. But infants who are fed infant formula will not need them until they have less than 500 ml of infant formula a day, because these products are fortified with vitamin D. Breastfed infants may need drops containing vitamin D from 1 month of age if their mother has not taken vitamin D supplements throughout pregnancy”.26

Again, always talk with your pediatrician about what your and your babies’ individual needs are. 


Take away Points:

  • Vitamin D is an essential nutrient for a healthy pregnancy and baby
  • Deficiency is a widespread problem and testing is indicated in most pregnant women
  • Optimal blood levels of >30 ng/ml are needed, possibly higher for optimal mood and immune function
  • Increase intake through sun exposure, food, and supplementation, with recommended dosage seeming to be a little more than what an average prenatal gives you

Being knowledgeable about our own risk factors, seeking out testing from a qualified healthcare professional, and supplementing safely are all very smart moves you can start making today.


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  21. Tripkovic, L., et al. (2012). Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. The American Journal Of Clinical Nutrition, 95(6), 1357-1364. doi:10.3945/ajcn.111.031070. Available from https://www.ncbi.nlm.nih.gov/pubmed/22552031

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  23. Cauley, J., Danielson, M., Boudreau, R., Barbour, K., Horwitz, M., & Bauer, D. et al. (2011). Serum 25-hydroxyvitamin D and clinical fracture risk in a multiethnic cohort of women: The women’s health initiative (WHI). Journal Of Bone And Mineral Research, 26(10), 2378-2388. doi:10.1002/jbmr.449. Available from https://www.ncbi.nlm.nih.gov/pubmed/21710614

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