Pregnancy and vitamin D

Vitamin D is important to maintain healthy levels of calcium and phosphorous, which are needed for strong bones and teeth. Your vitamin D needs are higher during pregnancy. Getting enough is important both for your own health and for your baby's development.

• 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 and rickets. 
• Rickets is a condition that affects bone development in children. Rickets can cause bone pain, poor growth and deformities of the skeleton. Deformities can be bowed legs, curvature of the spine, and thickening of the ankles, wrists and knees. Children with rickets are more likely to fracture their bones.

Read more about vitamin D and rickets.

You're at increased risk of having low levels of vitamin D if you:

• have naturally darker skin, eg if you're from Africa, South Asia or the Middle East
• have limited sun exposure because you regularly wear clothing that covers a lot of your skin (eg, veils or other clothing covering your legs, arms and face)
• stay inside a lot, eg, for work, because of previous melanoma or 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 taking a medicine that affects vitamin D, such as some epilepsy medicines.

If you're in any of these groups, a vitamin D supplement may be recommended during pregnancy. 

The main source of vitamin D is sun exposure – most people can get enough vitamin D through exposure to sunlight.  Some foods contain vitamin D but it's hard to get enough through diet alone.

Sun exposure

Exposing your skin to the sun must be done sensibly because sun increases the chance of skin cancer. Wear sunscreen and never get sunburnt. Read more about sensible sun exposure.

• In Aotearoa New Zealand, 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 to 8 minutes of sun exposure may be enough.
• During May to August outdoor activity is best around noon, as about 30 to 50 minutes of sun exposure is needed to produce the same amount of vitamin D during the winter months
• People with darker skin may require 3 to 6 times more sun exposure to achieve equivalent levels of vitamin D production. 

Sunlight directly on your skin is important – sunlight through glass doesn't work, as glass blocks out the ultraviolet B rays needed to make Vitamin D.

Image credit: Depositphotos

Food sources of vitamin D

Vitamin D is found in small quantities in a few foods such as fatty fish (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.

Supplements for vitamin D

It's not recommended to take supplements other than folic acid and iodine when you're pregnant. If you're thinking of (or already) taking a supplement discuss it with your healthcare provider.  

However, if you're at high risk of vitamin D deficiency, talk to your midwife, doctor or dietitian. Your doctor or midwife will prescribe a vitamin D supplement called colecalciferol. During pregnancy daily drops, rather than tablets, are recommended. The dose is 1 to 2 drops each day (400 to 800 IU). This medicine is funded by the government. It may be that you only need it during the winter months. If you are prescribed a vitamin D supplement, it's important that you take it regularly to make sure your growing baby has enough vitamin D.