Vitamin D helps to maintain your muscle and bone strength. It also helps your body absorb calcium from food. Vitamin D may also give you protection against developing diseases such as diabetes, heart disease and some types of cancer.

Adults who have vitamin D deficiency do not usually feel any different but in some cases they may have sore or weak muscles or have weakened bones.

In pregnancy, vitamin D also helps to develop your baby’s bones. If you have a vitamin D deficiency it can affect the amount of calcium your baby has in their bones. In severe deficiency this can cause a bone deformity called rickets.

Most of our vitamin D is made in our skin by the sun’s ultraviolet rays. You are at risk of a vitamin D deficiency if you have too little sunlight exposure. This may happen if you spend a lot of time indoors or cover most of your skin with clothing.

It is important to get enough sunlight to produce vitamin D without increasing your risk of skin cancer.Vitamin D levels are checked with a blood test early in pregnancy. If the level is too low, you will be advised to take vitamin D supplements. You should take the amount of supplement prescribed by your doctor or midwife. This amount may change depending on what your blood level is. Sometimes higher doses are needed at first to build your level up. There is no danger of overdose with these amounts.

Women who have had low vitamin D levels during pregnancy are encouraged to continue to take vitamin D supplements until they finish breastfeeding, once you stop taking supplements you should have your level checked from time to time by your GP to see if it has stayed in the normal range.