Vitamin D is essential for strong bones, muscles and overall health. It is particularly important in pregnancy, where vitamin D is needed for your baby's bone and teeth development.
Why is vitamin D important in pregnancy?
Vitamin D is important to maintain healthy levels of calcium and phosphorous, which are needed for strong bones and teeth. It is important both for your own health and wellbeing and for your baby's development in pregnancy.
- If you have low vitamin D levels (called vitamin D deficiency), your baby is also at risk of having low vitamin D levels. This puts your baby at risk of complications such as abnormal bone growth, delayed physical development and rickets.
- Rickets is a condition that affects bone development in children. Rickets can cause bone pain, poor growth and deformities of the skeleton, such as bowed legs, curvature of the spine, and thickening of the ankles, wrists and knees. Children with rickets are also more likely to fracture their bones.
Read more about vitamin D.
Who is at risk of vitamin D deficiency?
You are at increased risk of having low levels of vitamin D if you:
- have naturally darker skin, such as people from Africa, the Indian subcontinent and the Middle East
- have limited sun exposure from regularly wearing clothing that covers a lot of your skin (eg, veils or other clothing covering your legs, arms and face)
- stay inside a lot due to poor health
- live in the South Island (especially south of Nelson and Marlborough) and get little time outdoors in the middle of the day between May and August
- have liver or kidney disease
- are on certain medicines that affect vitamin D, such some epilepsy medicines.
How do I get enough vitamin D?
The main sources of vitamin D are sun exposure and foods that contain vitamin D. Getting enough vitamin D is hard to achieve through diet alone. Most people can get enough vitamin D through exposure to sunlight.
If you are at risk of vitamin D deficiency, talk to your midwife, doctor or dietitian. Your doctor can prescribe a vitamin D supplement called colecalciferol, which is a tablet you take once a month during your pregnancy.
Most people can get enough vitamin D through exposure to sunlight.
- From September to April, a daily walk in the early morning or late afternoon with your face, arms and hands exposed is recommended.
- At the height of summer, as little as 6–8 minutes of sun exposure may be enough.
- During May to August outdoor activity is best scheduled around noon, as about 30–50 minutes of sun exposure is needed to produce the same amount of vitamin D.
- People with darker skin may require 3 to 6 times more sun exposure to achieve equivalent levels of vitamin D production.
Sunlight directly on the skin is important – sunlight through glass doesn't work, as glass blocks out the ultraviolet B rays needed to make Vitamin D.
Exposing your skin to the sun must be sensible. You should never get sunburnt. Read more about sensible sun exposure.
Food sources of vitamin D
Vitamin D is found in small quantities in a few foods such as fatty fish (North Sea salmon, herring and mackerel).
Liver, eggs and fortified foods such as margarine and some low-fat dairy products (milk and yoghurt) also contain very small amounts of vitamin D.
However, it's hard to get enough vitamin D through your diet alone.
Supplements for vitamin D
It is not recommended to take supplements other than folic acid and iodine (such as multivitamins for pregnancy) and you must only take supplements on the advice of your doctor or midwife.
However, if you are at high risk of vitamin D deficiency, talk to your midwife, doctor or dietitian. Your doctor can prescribe a vitamin D supplement called colecalciferol, which is a tablet you take once a month during your pregnancy. Some women may only need this during the winter months. If your doctor prescribes some vitamin D supplements for you, it is important that you take them regularly to ensure your developing baby has enough vitamin D.
Vitamin D and pregnancy Ministry of Health, NZ. This information is also available in Māori, Arabic, Simplified Chinese, Traditional Chinese, Cook Islands Māori, Hindi, Korean, Samoan, Tagalog and Tongan
- Vitamin D and calcium supplementation in primary care: an update BPAC, NZ, 2016
- Eating and Activity Guidelines Ministry of Health, NZ, 2020
|Dr Helen Kenealy is a geriatrician and general physician working at Counties Manukau DHB. She has a broad range of interests and has worked in a variety of settings including inpatient rehabilitation, orthgeriatrics and community geriatrics.|