If a woman suffers from a vitamin D deficiency during pregnancy, it could result in bone abnormalities in the newborn child, such as infant brittle bone disease, also known as ‘rickets’.
Rickets is a defect affecting the accumulation of minerals or calcium in the bones of an infant before those bones have fully developed. It occurs when there is a lack of, or irregularities affecting the production and breakdown of vitamin D, phosphorus and calcium. This can lead to the bones of the newborn child being easily broken or abnormal in form. The disease is most common to developing countries and its major cause is vitamin D deficiencies, while other, less common causes include calcium deficiencies.
Currently, it is not necessary for all pregnant women to undergo vitamin D level screening. However, it is recommended for women who fall into the high risk category. Screening identifies 25-hydroxy vitamin D levels in the blood of pregnant women, and where a woman is found to have a vitamin D deficiency, specialists will usually recommend vitamin D supplements of 1000-2000 IU (International Units) per day, as this is regarded as a safe amount for the unborn child.
Vitamin D is a vitamin that is broken down by fat; it is found in large amounts in foods such as fresh milk, fruit juices, fish oils and vitamin D supplements. Additionally, vitamin D is produced by the skin when exposed to sunlight and it also helps to absorb calcium from the intestines for use in bone growth.
There is scientific evidence available which shows that vitamin D deficiencies are common in pregnant women, especially in high risk groups. These include, for instance, women who consume a vegetarian diet; those who do not get enough sunlight, such as people who reside in colder countries and wear multiple layers of clothes to protect against the elements; as well as people with darker skin.
In newborn children, vitamin D levels in the blood will depend on the blood vitamin D levels present in their mother. If the pregnant woman is at a high risk of developing a vitamin D deficiency, the newborn infant will also carry the same heightened risk.
Women who are categorized as being at high risk of developing a vitamin D deficiency should undergo a blood test to assess vitamin D (25-OH-D) levels. If those levels are found to be lower than 32 ng/ml (80nmol/L), the woman is regarded as suffering from a vitamin D deficiency, and should therefore begin taking vitamin D supplements of 1000-2000 IU per day. Usually, vitamin D levels found in regular supplements taken by pregnant women total just 400 IU per tablet, which is not sufficient to redress the imbalance experienced by those with a deficiency.
Therefore, it is crucial that pregnant women who fall into any of the high risk categories undergo blood vitamin D level screening.
Committee opinion, The American College of Obstetricians & Gynecologist 2011.
M.D., Faculty of Medicine, Srinakharinwirot University, 1997.