Vitamin D During Pregnancy: Importance, Dosage And Foods

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Vitamin D, also known as calciferol or the ‘sunshine vitamin,’ helps calcium absorption in the intestine and regulates calcium and phosphate levels in the body. Severe deficiency of vitamin D during pregnancy has been linked to poor bone health in babies. Besides, it may be responsible for certain pregnancy complications, such as preeclampsia. Most pregnant women can meet their daily vitamin D needs by consuming vitamin D-rich foods, sufficient exposure to sunlight, and taking prenatal vitamins. Yet, some women may develop vitamin D insufficiency or deficiency in some cases. Keep reading to learn more about the role of vitamin D in pregnancy and ways to improve its intake (1) (2).

Why Is Vitamin D Important During Pregnancy?

Vitamin D has two types – vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). While you can get vitamin D2 from edible mushrooms and supplements, vitamin D3 can be obtained from sun exposure, animal-origin foods, and supplements. However, both these vitamins need to convert into active vitamin D, which the body can utilize.

The biologically active metabolite of vitamin D, 1,25-dihydroxy vitamin D, helps in calcium absorption that supports bone mineralization and growth. During pregnancy, the levels of active vitamin D increase, particularly during the second and third trimesters, to support the fetus’ proper bone and muscle development. The increased calcium absorption from the gut and the fetus’ high calcium requirements are the main reasons for this increase. Thus, maintaining adequate vitamin D levels during pregnancy is essential.

Maternal vitamin D deficiency has been associated with skeletal homeostasisⁱBalance between the formation of bones and the continuous destruction (resorption) by osteoclasts disorders, congenital rickets, and an increased risk of fractures in the baby (2). Additionally, studies have reported links between low vitamin D levels and disorders such as metabolic syndrome, childhood allergy, asthma, and neurodevelopmental issues (3) (4) (5).

Furthermore, scientists theorize that active vitamin D also plays the role of an immune modulator that supports maternal tolerance to the foreign fetus since its DNA is half that of the mother’s. It is based on the finding that levels of the said metabolite increase earlier than the increase in requirement for the development of the fetal skeletal system (6).

Furthermore, anecdotal evidence highlights that consumption of vitamin D supplements may help reduce the risk of preterm birth. However, more research is needed to further ascertain this claim.

A Cochrane review further suggests that vitamin D supplements during pregnancy may reduce the risks of (4):

• Developing preeclampsiaⁱA condition characterized by high blood pressure and protein in urine and gestational diabetes
• Low-birthweight in babies
• Postpartum hemorrhageⁱA pregnancy complication characterized by heavy vaginal bleeding after childbirth

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Did you know?

Vitamin D is a potent hormone produced in the brain (neurosteroid) that protects brain cells and helps them to grow (7).

How Much Vitamin D Should You Take During Pregnancy?

According to the US National Institutes of Health (NIH), pregnant women require 15mcg or 600IU of vitamin D daily, while the World Health Organization (WHO) suggests a daily requirement of 5mcg or 200 IU

(1) (8). However, the recommendations for taking supplements may vary depending on an expecting woman’s vitamin D levels, overall health, and risk of developing vitamin D deficiency.

The UK National Health Services (NHS) advises a daily vitamin D supplement of 10mcg (or 400 IU) during pregnancy, especially during the autumn and winter months (between September and March), as there is less sun exposure (9) (10). You may require 1000 to 2000 IU of vitamin D daily if a deficiency is detected (2). Consult your doctor to know the exact dose suitable for you, keeping your health and dietary practices in consideration.

Expert says

The NHS mentions that more than 100 micrograms (4,000IU) of vitamin D per day can be harmful and should be avoided (9).

Do Prenatal Vitamins Have Enough Vitamin D?

Most prenatal vitamins contain 400IU of vitamin D, which may not be sufficient to fulfill your daily vitamin D requirement during pregnancy

(2). Therefore, you need to consult your doctor and get vitamin D supplements prescribed accordingly. Additionally, take vitamin D supplements with food for better absorption.

What To Know About Vitamin D Deficiency During Pregnancy?

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Large epidemiological studiesⁱStudies that deal with the prevalence of a health condition in different groups, its natural history, and causes have shown that many women, including pregnant women, have vitamin D deficiency. Vitamin D levels in neonates depend primarily on the mother’s vitamin D status; hence maternal vitamin D deficiency increases the baby’s risk of being deficient in the vitamin. The risk factors for vitamin D deficiency in pregnant women include (1) (2).

• Being vegetarian or vegan
• Limited sun exposure due to living in cold climates, residing in higher latitudes, or wearing sun and winter protective clothing
• Always wearing sunscreen on all exposed skin areas/surfaces
• Having a dark complexion (due to higher melanin content)
• Having a raised BMI as the requirements for vitamin D may be higher.

It is advised to consult your doctor if you feel you may require specific vitamin D supplementation.

Point to consider

Sun exposure is good for vitamin D synthesis. However, prolonged exposure without wearing protective clothing or sunscreen is not advisable as it may raise the risk of skin cancer (11). It may also increase the risk of overheating (12).

Foods High In Vitamin D

The notable food sources of vitamin D to be included in the diet chart for pregnant women (1) (9):

• Oily fish such as herring, mackerel, salmon, and sardines
• Eggs, particularly egg yolks
• Red meat
• Mushrooms (sun exposure may elevate mushrooms’ vitamin D levels) (13)
• FortifiedⁱWhen a vitamin or mineral is deliberately added to a food milk that includes dairy and plant-based milk such as soy milk and almond milk
• Fortified orange juice, cereals, and yogurt

Quick fact

Cod liver oil is a rich source of vitamin D, but it is usually avoided during pregnancy as it contains vitamin A (14). Too much vitamin A (retinol) intake during pregnancy could adversely affect the baby (15).

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Infographic: How To Meet Your Vitamin D Needs During Pregnancy

Vitamin D needs during pregnancy increase. Besides supporting fetal bone development, optimum maternal vitamin D levels are essential to perform crucial metabolic and immunological functions. Thus, prompt identification and treatment of vitamin D insufficiency or deficiency are vital. The infographic below shares a few practical and effective ways would-be moms can maintain healthy vitamin D levels during pregnancy.

Illustration: Momjunction Design Team

Illustration: Vitamin D During Pregnancy: Importance Dosage And Foods

Image: Stable Diffusion/MomJunction Design Team

Discover how Vitamin D can help you and your child stay healthy. Join us to learn more about this subject.

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Reviewer Author Editor Fact Checker

Hannah WhittakerRD

Hannah is a pregnancy and pediatric dietitian with seven years of experience. She specializes in milk allergy and vegan pregnancy. She has been working with women and children for nearly 20 years, the last seven years as a registered dietitian.

Read full bio of Hannah Whittaker

Dr. Joyani DasM.Pharm, PhD

Dr. Joyani Das did her post-graduation from Birla Institute of Technology, Mesra and PhD in Pharmacology. Previously, she worked as an associate professor, faculty of Pharmacology, for two years. With her research background in preclinical studies and a zeal for scientific writing, she joined MomJunction as a health writer.

Read full bio of Dr. Joyani Das

Swati PatwalM.Sc. (Food & Nutrition), MBA

Swati Patwal is a clinical nutritionist, a Certified Diabetes Educator (CDE) and a toddler mom with more than a decade of experience in diverse fields of nutrition. She started her career as a CSR project coordinator for a healthy eating and active lifestyle project catering to school children.

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Aneesha AmonzMSc

Aneesha holds a Bachelor's degree in Biotechnology from USTM, Meghalaya and Master’s degree in Applied Microbiology from VIT, Vellore. With two years of experience, she has worked on different research projects in the field of Food Sciences.

Read full bio of Aneesha Amonz