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Vitamin D and It's Role in Pregnancy

Updated: Nov 29, 2023

A developing baby requires the mother to be healthy and well-nourished. This is because the mother is the main source of nutrition, energy, and protection to the baby. If there are disruptions in the mother’s body, this will also cause disruption to the pregnancy.

Vitamin D has been heavily researched for its role in pregnancy. The developing baby ONLY gets it’s Vitamin D from it’s mother and high concentrations of Vitamin D can be found in the umbilical cord. Recent evidence estimates that over 40% of the U.S. population is deficient in Vitamin D. People with darker skin fall at an even greater risk of deficiency with 63% of hispanics and 82% of black people are deficient (1). The American Pregnancy Association estimates that 40-60% of pregnant women may be deficient in Vitamin D (2).

How do we get Vitamin D?

Vitamin D3 is formed in the skin after exposure to UV rays, it can also be acquired through dietary supplementation. Once in circulation, Vitamin D is converted to 25-hydroxyvitamin D (25(OH)D) this conversion primarily occurs in the liver. This form of Vitamin D is then converted into the hormonal form-- 1,25-dihydroxyvitamin D3 (1,25(OH)2D) this conversion occurs in the kidneys.

Vitamin D metabolism changes during pregnancy. Fetal levels of 1,25(OH)2D will become twice that of a non-pregnant adult and will continue to rise to a point where in non-pregnant adults, these levels may be considered toxic due to calcium regulation (3). However, in this gestational state, calcium levels are not yet affected. This suggests that rising Vitamin D levels are not as likely to correlate with the demand for calcium, but for enhanced immune response.

Vitamin D Recommendations for Pregnancy

Unfortunately, medical recommendations are not reflecting the most current research, the Institute of Medicine recommends 400-600 IU Vitamin D per day and 0 IU are recommended by the World Health Organization (4) stating that there are simply no requirements for Vitamin D during pregnancy.

A study looked at pregnant women supplemented with Vitamin D during pregnancy. They analyzed levels of Vitamin D when pregnant women were dosed with 400 IU, 2000 IU, or 4000 IU daily. It was found that the women receiving 4000 IU had the highest Vitamin D concentrations (5). Researchers found that in this group, the women who received the highest amount of Vitamin D had the lowest number of pregnancy complications including: preeclampsia, gestational diabetes, preterm labor, caesarean section births, and infections (5).

One of my routine lab tests I recommend is Vitamin D! Since I live in a state with less sun exposure in the south, I supplement with Vitamin in the fall, winter and spring. Vitamin D testing and supplementation can be inexpensive and make a massive impact on overall immune and reproductive health.


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If you are looking for preconception counseling, are having difficulty conceiving, and/or have suffered from miscarriage(s) you can click here to sign up with a complimentary 15 minute phone call with me. We can discuss your goals at that time and determine whether or not we will be a good fit for each other. We will discuss necessary nutrients, dietary options, as well as lifestyle and exercise programs catered to YOU specifically to help you reach your health goals.

About Dr. Zaremba:

Dr. Zaremba received her bachelor's degree from Western Michigan University in Biomedical Sciences and minored in Chemistry and Psychology. She completed her doctoral training at Palmer College of Chiropractic. During her time in school, she took post-doctoral training through The Clinic on Disease and Internal Disorders (CDID) earning her a Diplomate from the American Board of Chiropractic Internists (DABCI).


This web site offers health, wellness, fitness and nutritional information and is provided for informational purposes only. This information is not intended as a substitute for the advice provided by your physician or other healthcare professional. You should not rely on this information as a substitute for, nor does it replace, professional medical advice, diagnosis, or treatment, Always speak with your physician or other healthcare professional before taking any medication or nutritional, herbal or homeopathic supplement, or using any treatment for a health problem. If you have or suspect that you have a medical problem, contact your health care provider promptly. Do not disregard professional medical advice or delay in seeking professional advice because of something you have read on this web site. The use of any information provided on this web site is solely at your own risk. Nothing stated or posted on this web site or available through any services offered by Dr. Katie Zaremba DC, Dr. Katie Zaremba LLC, are intended to be, and must not be taken to be, the practice of medicine. Information provided on this web site DOES NOT create a doctor-patient relationship between you and any doctor affiliated with our web site. Information and statements regarding dietary supplements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease.


  1. Meltzer DO, Best TJ, Zhang H, Vokes T, Arora V, Solway J. Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results. JAMA Netw Open. 2020;3(9):e2019722. doi:10.1001/jamanetworkopen.2020.19722

  2. Samimi M, Foroozanfard F, Amini F, et al. Effect of vitamin D supplementation on unexplained recurrent spontaneous abortion: a double-blind randomized control trial. Glob J Health Sci. 2017;9(3):95-102.

  3. Hollis, B., Wagner, C. New insights into the vitamin D requirements during pregnancy.Bone Res 5, 17030 (2017).

  4. World Health Organisation. Vitamin D Supplementation in Infants. Geneva: World Health Organisation. 2014.

  5. Hollis, B.W., Wagner, C.L. Vitamin D and Pregnancy: Skeletal Effects, Nonskeletal Effects, and Birth Outcomes. Calcif Tissue Int 92, 128–139 (2013).

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