Vitamin D is essential during pregnancy for your baby's skeletal development and your own bone health. Whilst oily fish, eggs, and fortified foods provide some vitamin D, obtaining adequate amounts through diet alone is challenging in the UK. The NHS recommends all pregnant women take a daily 10 microgram (400 IU) vitamin D supplement throughout pregnancy and whilst breastfeeding. This article explores which foods contain vitamin D, how much you need, and why supplementation remains crucial for maternal and foetal wellbeing, particularly given the UK's limited sunlight exposure during winter months.

Why Vitamin D Matters During Pregnancy

Vitamin D plays a crucial role throughout pregnancy, supporting both maternal health and foetal development. This fat-soluble vitamin functions as a hormone precursor, regulating calcium and phosphate metabolism essential for building your baby's skeleton and teeth. During pregnancy, your body's physiological needs for vitamin D change to support the developing foetus whilst maintaining your own bone health.

Key functions during pregnancy include:

• Facilitating calcium absorption from the digestive tract

• Supporting foetal skeletal mineralisation and growth

• Contributing to immune system function in both mother and baby (though evidence is still evolving)

• Potentially supporting placental development and function (based on observational studies)

Research suggests that adequate vitamin D status during pregnancy may be associated with reduced risk of certain complications, though evidence continues to evolve. The UK's Scientific Advisory Committee on Nutrition (SACN) recognises vitamin D as particularly important during pregnancy. Maternal vitamin D crosses the placenta, making the mother's status the primary determinant of foetal vitamin D levels.

Vitamin D deficiency during pregnancy has been associated with various adverse outcomes in observational studies, including pre-eclampsia, gestational diabetes, and low birth weight, though causality has not been definitively established. What remains clear is that maintaining adequate vitamin D status supports optimal bone health for both mother and baby. The NHS and NICE (NG201) recommend that all pregnant women should take a daily vitamin D supplement of 10 micrograms (400 IU), particularly given the UK's limited sunlight exposure during winter months and the difficulty in obtaining sufficient amounts through diet alone.

Food Sources of Vitamin D for Pregnant Women

Obtaining adequate vitamin D through diet alone presents a considerable challenge, as relatively few foods naturally contain significant amounts of this nutrient. However, incorporating vitamin D-rich foods into your pregnancy diet contributes towards meeting your requirements and provides additional nutritional benefits.

Naturally rich sources include:

Oily fish represent the most concentrated dietary source of vitamin D. A 140g portion (a standard portion) of cooked salmon provides approximately 10–13 micrograms, whilst mackerel offers 8–10 micrograms. Sardines, trout, and herring are also excellent choices. The NHS advises pregnant women to limit oily fish to two portions weekly due to potential pollutant content. Canned tuna is not classified as oily fish but has separate guidance: limit to 4 medium-sized cans or 2 tuna steaks per week due to mercury content. Avoid shark, marlin and swordfish completely during pregnancy.

Egg yolks contain modest amounts of vitamin D, with one large egg providing approximately 1–2 micrograms. The vitamin D content varies depending on the hen's diet and sun exposure. Eggs also provide high-quality protein, choline, and other nutrients beneficial during pregnancy. British Lion marked eggs (with the red lion stamp) can be eaten raw or runny in pregnancy. If eggs don't have the British Lion mark, they should be cooked thoroughly until the whites and yolks are solid.

Fortified foods contribute to vitamin D intake in the UK. Many breakfast cereals are fortified with vitamin D, typically providing 1.5–2.5 micrograms per serving. Unlike some countries, cow's milk in the UK is generally not fortified with vitamin D. However, many plant-based milk alternatives (soya, oat, almond), some yoghurts, and spreads are fortified, though levels vary considerably between products. Always check nutrition labels, as fortification is not universal.

Mushrooms exposed to ultraviolet light during growth can provide vitamin D2 (ergocalciferol), though amounts vary and vitamin D2 is less potent than the D3 form found in animal products. Red meat contains small amounts of vitamin D, though liver should be avoided during pregnancy due to high vitamin A content, which can be harmful to your baby. Despite these dietary sources, most pregnant women require supplementation to achieve recommended levels, particularly in the UK where sunlight-induced vitamin D synthesis is limited for much of the year.

How Much Vitamin D Do You Need When Pregnant?

The UK Department of Health recommends that all pregnant and breastfeeding women take a daily supplement containing 10 micrograms (400 IU) of vitamin D. This recommendation applies throughout pregnancy and whilst breastfeeding, regardless of the season or dietary intake. The reference nutrient intake (RNI) for vitamin D during pregnancy is 10 micrograms daily, the same as for the general adult population.

This guidance reflects the reality that achieving adequate vitamin D status through diet and sunlight exposure alone is extremely difficult in the UK. During autumn and winter months (October to March), sunlight in the UK does not contain sufficient UVB radiation for the skin to synthesise vitamin D. Even during summer months, factors such as clothing, sunscreen use, time spent indoors, skin pigmentation, and latitude affect vitamin D production.

NICE guidance (NG201) specifically recommends that healthcare professionals inform pregnant women about the importance of vitamin D supplementation. Women may access vitamin D supplements through the Healthy Start scheme if eligible, which provides free vitamins containing the recommended 10 micrograms of vitamin D, along with vitamin C and folic acid. You can check eligibility on the NHS Healthy Start website.

Certain groups face higher risk of deficiency and may require higher supplementation doses under medical supervision:

• Women with darker skin pigmentation (African, African-Caribbean, or South Asian heritage)

• Women who have limited sun exposure (those who cover their skin for cultural reasons or are housebound)

• Women with a BMI above 30 kg/m²

• Women with malabsorption conditions (coeliac disease, Crohn's disease, chronic pancreatitis)

If you fall into a higher-risk category, discuss with your GP or midwife, as they may recommend testing your vitamin D levels and prescribing higher-dose supplementation if deficiency is confirmed. The standard pregnancy multivitamin may not contain adequate vitamin D, so check the label or take a separate vitamin D supplement. Avoid supplements containing vitamin A (retinol) and cod liver oil, as excessive vitamin A can harm your developing baby. Do not exceed 100 micrograms (4,000 IU) of vitamin D daily unless specifically prescribed by your healthcare provider.

Signs of Vitamin D Deficiency During Pregnancy

Vitamin D deficiency during pregnancy often presents subtly or remains asymptomatic, making it difficult to identify without blood testing. Many women with inadequate vitamin D levels experience no obvious symptoms, which is why universal supplementation is recommended rather than relying on symptom-based detection.

When symptoms do occur, they may include:

Musculoskeletal symptoms are most common. You might experience bone pain, particularly in the lower back, pelvis, or ribs. Muscle weakness, aching, or fatigue may develop, though these symptoms overlap considerably with normal pregnancy discomforts, making attribution challenging. Some women report difficulty climbing stairs or rising from a seated position due to proximal muscle weakness.

Generalised fatigue beyond typical pregnancy tiredness may indicate deficiency, though this is non-specific. Mood changes, including low mood, have been associated with low vitamin D status, though there is no official link establishing causality during pregnancy.

Severe deficiency can lead to osteomalacia (softening of the bones), presenting with bone pain, tenderness, and increased fracture risk. This is uncommon but represents a serious complication requiring medical treatment.

Your baby may also be affected by maternal vitamin D deficiency. Neonatal complications can include hypocalcaemia (low calcium levels), which may cause seizures, poor feeding, or irritability in the newborn period. Seek emergency medical care immediately if your newborn shows signs of seizures. There is emerging evidence suggesting associations between maternal deficiency and childhood rickets, though supplementation programmes have reduced this risk significantly.

When to contact your GP or midwife:

• Persistent bone or muscle pain that interferes with daily activities

• Unexplained muscle weakness

• If you belong to a high-risk group and haven't discussed vitamin D supplementation

• Concerns about your vitamin D status

Routine vitamin D testing is not recommended for all pregnant women in the UK. Your healthcare provider can arrange a blood test measuring 25-hydroxyvitamin D [25(OH)D] levels if deficiency is suspected or if you're in a high-risk group. Levels below 25 nmol/L indicate deficiency, whilst 25–50 nmol/L suggests insufficiency. Treatment involves higher-dose vitamin D supplementation under medical supervision, with dosing regimens prescribed and monitored by a healthcare professional. Remember that prevention through routine supplementation of 10 micrograms daily remains the most effective strategy for maintaining adequate vitamin D status throughout pregnancy.

Frequently Asked Questions