A vitamin D deficiency during pregnancy may harm the fetus

A vitamin D deficiency during pregnancy may harm the fetusA new British study that is published in British Journal of Nutrition shows that getting too little vitamin D during pregnancy has a negative effect on the social development and motor skills of the toddler. Vitamin D is believed to play a role in brain development. It is vital for the pregnant mother to pay careful attention to getting enough vitamin D all year round, as our modern lifestyle with indoor activities, our frequent use of sunscreen with high sun factor, being overweight, and having dark skin contribute to the widespread deficiency of this nutrient.

All cells in the body have vitamin D receptors that are important for our nervous system, brain, calcium uptake, bones, muscles, brain, and immune system. Getting too little vitamin D during pregnancy will not only harm the mother’s health but can also have a negative impact on the health and development of the child both in the short and in the long run.

A vitamin D-deficient mother gives her child a bad start in life

Researchers from the University of Surrey and the University of Bristol studied levels of vitamin D in over 7,000 pregnant women. They later discovered that women with low vitamin D levels in their blood (less than 50 nmol/l of blood) during pregnancy had a 25% increased risk of giving birth to a child who at the age of two-and-a-half did not perform as well in tests of motor skills. The test included studies of the children’s physical coordination – including kicking a ball, balancing, and jumping. The researchers also tested the children’s fine motor skills by asking them to hold a pencil and build a tower with blocks.
Vitamin D deficiency in the pregnant women also had a negative impact on the children’s social development at the age of three-and-half years. However, the scientists failed to find a link between vitamin D status during pregnancy and other skills (IQ and reading) in the children at the age of 7-9 years. It is apparently only small children whose motor skills and mental skills are affected negatively by their mothers’ vitamin D deficiency.

Vitamin D controls brain development and numerous other things

Earlier animal research reveals that the cognitive functions of the fetus are negatively affected, if the mother lacks vitamin D. The scientists assume that interactions between vitamin D and dopamine, a neurotransmitter in the brain, plays a vital role in the neurological development, including those parts of the brain that control motor skills and social skills. According to Dr. Andrea Darling from the University of Surrey, we should not underestimate the importance of vitamin D, which has numerous other functions in the body. It is already common knowledge that vitamin D is important for our calcium uptake and for bone health, and having sufficient amounts of vitamin D in the blood is linked to a lower risk of osteoporosis (fragile bones), cardiovascular diseases, infections, autoimmune disorders, and diabetes.

Lack of vitamin D may also increase the child’s risk of weak bones and serious diseases

According to earlier studies, a vitamin D deficiency during pregnancy may increase the child’s risk of weak bones, autism, and sclerosis later in life. Professor Nicolas Harvey at the University of Southampton underlines how important it is for the child’s health that the mother has sufficient amounts of vitamin D in her blood during pregnancy. As his studies clearly show, it is vital for the expecting mother to optimize her levels of vitamin D in the blood and pay special attention to individual factors such as her weight and her term.

Vitamin D sources and precautions

Our primary vitamin D source is the sun in the summertime. We also get the nutrient from oily fish (such as salmon, sardines, mackerel, and tuna), eggs, butter, and liver, but the amount of vitamin D in the diet is negligible. Pregnant women are advised not to consume predatory fish (mainly tuna), as they contain mercury that may harm the fetus.

Did you know that you can easily produce 30-100 micrograms of vitamin D on a nice and warm summer day? However, supplements are necessary during winter because we only get very little vitamin D from the diet.

Recommendations for pregnant women and infants

Women planning to become pregnant, and women who have already conceived, should have their vitamin D levels checked in order to make sure that they have the optimal vitamin D concentration in their blood. With regard to supplementation, the European Food Safety Authority (EFSA) has set the safe upper intake level for vitamin D at 100 micrograms per day for adults, including pregnant and lactating women. Excessive vitamin D levels in the blood during pregnancy may harm the fetus, but this would take much higher doses. It is not possible to get too much vitamin D from sunlight and food.

Vitamin D supplements and absorption

Because vitamin D is lipid-soluble, the best absorption and utilization of the nutrient is obtained when it is contained in oil and soft gel capsules.

Vitamin D deficiency and poor utilization of the nutrient may be caused by

  • Lack of sunlight during the summer period
  • Having dark skin
  • Eating a low-fat diet (without oily fish, eggs, and other good vitamin D sources)
  • Getting too much calcium from dairy products and supplements
  • Alcoholism
  • Overweight and diabetes
  • Use of sunscreen with a sun factor higher than 8 (which blocks vitamin D synthesis in the skin)
  • Prolonged use of cholesterol-lowering drugs (statins) and certain other types of medicine
  • Old age and thin skin


Andrea L. Darling et al. Association between maternal vitamin status in pregnancy and neurodevelopmental outcomes in childhood: results from the Avon Longitudinal Study of Parents and Children. (ALSPAC) British Journal of Nutrition, 2017

University of Surrey. Insufficient levels of vitamin D in pregnancy detrimental to child development. ScienceDaily, July, 2017

Khaled Sall et al. Randomized controlled trial of vitamin D supplementation in children with autism spectrum disorder. Journal of Child Psychology and Psychiatry. 2016

Alberto Ascherio, MD, DrPH et al. Vitamin D Status During Pregnancy and Risk of Multiple Sclerosis in Offspring at Women in the Finnish Maternity Cohort. JAMA Neurol. March 2016