Vitamin D supplementation during pregnancy is not only safe but actively recommended for all expectant mothers in the UK. Official guidance from the NHS, NICE, and the Department of Health and Social Care advises that pregnant women take a daily supplement containing 10 micrograms (400 IU) of vitamin D throughout pregnancy and whilst breastfeeding. This recommendation applies universally, regardless of diet, sun exposure, or season. Vitamin D plays a crucial role in foetal skeletal development and maternal bone health, with deficiency posing particular risks in the UK due to limited sunlight exposure, especially during autumn and winter months.

Can You Take Vitamin D While Pregnant?

Yes, you can and should take vitamin D during pregnancy. UK guidance recommends that all pregnant women take a daily supplement containing 10 micrograms (400 IU) of vitamin D throughout pregnancy and while breastfeeding. This advice comes from the NHS, NICE, and the Department of Health and Social Care.

Vitamin D is considered safe during pregnancy when taken at recommended doses. Unlike vitamin A (retinol), which should be avoided in supplement form during pregnancy, vitamin D at the advised supplementation level poses no known risks to the developing baby. The evidence for vitamin D supplementation in pregnancy is well-established for bone health, while research into other potential benefits is ongoing.

Pregnant women are considered at risk for vitamin D deficiency due to increased physiological demands and the transfer of vitamin D to the developing foetus. This is particularly relevant in the UK, where limited sunlight exposure—especially during autumn and winter months—means that most people cannot produce adequate vitamin D through skin synthesis alone. Women with darker skin, those who cover their skin for cultural or religious reasons, or those who spend limited time outdoors face even greater risk of deficiency.

The key message is clear: vitamin D supplementation during pregnancy is not only safe but actively recommended as part of routine antenatal care. If you have any concerns about taking supplements during pregnancy, discuss them with your midwife or GP, who can provide personalised advice based on your individual circumstances.

Why Vitamin D Is Important During Pregnancy

Vitamin D plays several critical roles during pregnancy, affecting both maternal health and foetal development. This fat-soluble vitamin functions more like a hormone in the body, regulating calcium and phosphate metabolism, which are essential for maintaining healthy bones, teeth, and muscles. During pregnancy, these functions become even more vital as the developing baby draws on the mother's nutrient stores.

For the developing baby, adequate maternal vitamin D is crucial for:

• Skeletal development: Vitamin D ensures proper bone mineralisation and growth of the foetal skeleton. Deficiency during pregnancy has been associated with poor bone development and an increased risk of rickets in infancy—a condition causing soft, weak bones that can lead to skeletal deformities.

• Immune system development: Some evidence suggests vitamin D may play a role in the development of the foetal immune system, though this research is still emerging and not definitive.

• Overall growth: Some research indicates that maternal vitamin D status may influence birth weight and foetal growth patterns, though more research is needed to fully understand these relationships.

For the mother, maintaining adequate vitamin D levels during pregnancy may help:

• Preserve bone health: Pregnancy places significant demands on maternal calcium stores. Vitamin D helps maintain bone density and prevents excessive bone loss during this period.

• Support muscle function: Adequate vitamin D contributes to normal muscle function, which is important throughout pregnancy and during labour.

• Pregnancy complications: Some observational studies have suggested associations between vitamin D deficiency and increased risk of pre-eclampsia, gestational diabetes, and preterm birth. However, interventional trial evidence is inconsistent, and there is no definitive recommendation beyond the standard 10 micrograms daily supplement.

The physiological changes of pregnancy, including increased blood volume and transfer of nutrients to the foetus, mean that vitamin D requirements are heightened during this time, making supplementation an important preventive health measure.

Recommended Vitamin D Dosage for Pregnant Women in the UK

The official UK recommendation for pregnant women is to take a daily supplement containing 10 micrograms (400 IU) of vitamin D. This guidance comes from the NHS, NICE, and the Office for Health Improvement and Disparities (formerly Public Health England). This dose applies throughout the entire pregnancy and should continue whilst breastfeeding.

This recommendation is universal—meaning it applies to all pregnant women, regardless of:

• Dietary vitamin D intake

• Time spent outdoors

• Season of the year

• Skin tone (though women with darker skin are at higher risk of deficiency)

The 10 microgram daily dose is considered both safe and effective for maintaining adequate vitamin D status during pregnancy. It is important to note that this is a preventive dose designed to ensure sufficient vitamin D levels in the general pregnant population, rather than a therapeutic dose for treating deficiency.

For women at higher risk of deficiency, healthcare providers may recommend higher doses. Risk factors include:

• Limited sun exposure (those who cover their skin, are housebound, or work indoors)

• Darker skin (African, African-Caribbean, or South Asian heritage)

• Obesity (BMI ≥30 kg/m²)

• Pre-existing vitamin D deficiency

• Malabsorption conditions (such as Crohn's disease or coeliac disease)

Routine vitamin D testing in pregnancy is not recommended unless deficiency is suspected. If you fall into a higher-risk category, your GP or midwife may check your vitamin D levels through a blood test and prescribe a higher therapeutic dose if deficiency is confirmed. Do not exceed 100 micrograms (4,000 IU) per day from all sources unless specifically advised by a healthcare professional.

Healthy Start vitamins, a UK government scheme, provides free vitamin supplements (including vitamin D) to eligible pregnant women and families on certain benefits or under 18 years of age. These supplements contain the recommended 10 micrograms of vitamin D, along with vitamin C and folic acid. Speak to your midwife about whether you qualify for this scheme.

When choosing a vitamin D supplement, look for products that clearly state the vitamin D content in micrograms or international units. Vitamin D3 (cholecalciferol) is generally preferred over D2 (ergocalciferol) as it is more effective at raising blood levels of vitamin D.

Safety and Side Effects of Vitamin D in Pregnancy

Vitamin D supplementation at the recommended dose of 10 micrograms (400 IU) daily is considered very safe during pregnancy with minimal risk of adverse effects. Extensive research has established its safety profile for both mother and baby when taken as directed.

Side effects at recommended doses are rare but may occasionally include:

• Mild gastrointestinal symptoms (nausea, constipation, or stomach discomfort)

• Headache

• Dry mouth or metallic taste

These effects are uncommon and typically mild when they do occur. If you experience persistent or bothersome symptoms, consult your midwife or GP. You can report any suspected side effects to the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk).

Vitamin D toxicity (hypervitaminosis D) is rare but can occur with excessive intake. Do not exceed 100 micrograms (4,000 IU) per day from all sources, as higher intakes can be harmful. Symptoms of toxicity include:

• Hypercalcaemia (elevated blood calcium levels)

• Nausea and vomiting

• Weakness and confusion

• Kidney problems

Important safety considerations:

• Do not exceed recommended doses unless specifically advised by a healthcare professional.

• Avoid vitamin A in supplements: During pregnancy, avoid all supplements containing vitamin A (retinol) and avoid liver products, as vitamin A can harm the developing baby.

• Check total vitamin D intake: If you are taking a pregnancy multivitamin that already contains vitamin D, check the amount to avoid doubling up unnecessarily. Most pregnancy multivitamins contain the recommended 10 micrograms.

• Inform healthcare providers: Always tell your midwife, GP, or any healthcare professional about all supplements you are taking, including vitamin D.

• Special precautions: Speak to your doctor before taking vitamin D supplements if you have kidney disease, hyperparathyroidism, sarcoidosis, or other conditions that might affect calcium metabolism.

• Medication interactions: Vitamin D may interact with certain medications, including enzyme-inducing anticonvulsants (such as phenytoin, carbamazepine, primidone), rifampicin, thiazide diuretics, and orlistat. Discuss with your doctor if you take any of these.

When to seek medical advice:

Contact your GP or midwife if you:

• Experience persistent nausea, vomiting, or abdominal pain whilst taking vitamin D

• Have accidentally taken a very high dose of vitamin D

• Have concerns about vitamin D deficiency or supplementation

• Are taking medications that may interact with vitamin D

For most pregnant women, vitamin D supplementation at the recommended dose represents a safe, evidence-based intervention that supports healthy pregnancy outcomes with minimal risk.

Getting Vitamin D from Food and Sunlight During Pregnancy

Whilst supplementation is recommended for all pregnant women in the UK, vitamin D can also be obtained through sunlight exposure and dietary sources. However, these sources alone are typically insufficient to meet the increased demands of pregnancy, particularly in the UK climate.

Sunlight and vitamin D synthesis:

The body produces vitamin D when skin is exposed to UVB radiation from sunlight. In the UK, this process is only effective between late March and September, when the sun is strong enough for adequate UVB exposure. During autumn and winter months, the sun's angle is too low for effective vitamin D synthesis, regardless of time spent outdoors.

Even during summer months, several factors limit vitamin D production:

• Sunscreen use: Sunscreen reduces UVB and vitamin D synthesis (though sun protection remains important for preventing skin damage and cancer)

• Clothing coverage: Cultural, religious, or personal preferences for covering skin

• Time of day: UVB exposure is most effective between 11am and 3pm

• Skin tone: Melanin reduces vitamin D synthesis; darker skin requires longer sun exposure

• Indoor lifestyle: Many people spend most daylight hours indoors

Pregnant women should continue to practice sun safety, avoid sunburn, and never use sunbeds. Relying on sunlight alone is not a practical or safe strategy for maintaining vitamin D levels.

Dietary sources of vitamin D:

Very few foods naturally contain significant amounts of vitamin D. The best dietary sources include:

• Oily fish: Salmon, mackerel, sardines, and fresh tuna (limit tuna to two fresh steaks or four medium cans per week during pregnancy due to mercury content)

• Egg yolks: Contain small amounts of vitamin D

• Fortified foods: Some breakfast cereals, fat spreads, and plant-based milk alternatives are fortified with vitamin D (check labels)

• Red meat: Contains small amounts of vitamin D

• Liver: Contains vitamin D but should be avoided during pregnancy due to high vitamin A content

Even with a diet rich in these foods, it is difficult to obtain the recommended 10 micrograms of vitamin D daily through diet alone. For example, you would need to consume approximately 100g of salmon or 10 eggs daily to meet requirements—an impractical and nutritionally unbalanced approach.

Practical recommendations:

• Take your daily 10 microgram vitamin D supplement as the primary and most reliable source

• Include vitamin D-rich foods in your diet when possible, as part of a balanced eating pattern

• Enjoy safe sun exposure during summer months (short periods without burning), but do not rely on this as your main source

• Consider fortified foods as an additional source, particularly if you follow a vegetarian or vegan diet

The combination of supplementation, dietary sources, and sensible sun exposure provides the best approach to maintaining optimal vitamin D status throughout pregnancy, supporting both your health and your baby's development.

Frequently Asked Questions