Norway study: One in three pregnant women deficient in vitamin D by pregnancy end

05 Jul 2018 --- One in three pregnant women in Norway has a vitamin D deficiency by the end of her pregnancy, a study published in PLOS One has shown. This number spikes in Norway’s dark winter months, which often do not provide enough sunlight for the sunshine vitamin to form, leading to rates of vitamin D deficient pregnant women reaching 50 percent. The study, which included 855 pregnant Norwegian women, highlights how many women are not taking government advice on vitamin D supplementation and calls for further action.

“It's tough to get enough vitamin D from dietary sources and for six months of the year the sunlight isn't sufficient at northern latitudes for our skin to make the vitamin. Even though we see the sun, it's too low for us to produce vitamin D,” says Miriam K. Gustafsson, the article's first author and a Ph.D. Candidate at the Norwegian University of Science and Technology's (NTNU) Department of Public Health and Nursing.

“We're covering ourselves in sunscreen in the summer to protect our skin and prevent cancer, but this can make it harder for the body to produce enough vitamin D,” she adds. 

Sufficient vitamin D delivers a wide array of vital health benefits and, therefore, deficiencies can have some serious repercussions:

• The vitamin is essential for the bone health of mother-child as vitamin D is necessary for calcium to be taken up by the intestine. In pregnancy, this take-up of calcium is critical to build the child’s bone mass and maintain that of the mother.
• Low levels of vitamin D have also been linked to an increased risk of childhood asthma and vitamin D supplements during pregnancy have been shown to reduce the child's risk of asthma. When the mother has too little vitamin D in her body, the risk of high blood pressure, preeclampsia and gestational diabetes may also increase.
• In a study published in The Lancet Diabetes & Endocrinology, researchers noted that among women planning to conceive after a pregnancy loss, those who had sufficient levels of vitamin D were more likely to become pregnant and have a live birth, compared to women with insufficient levels of the vitamin. Meaning, low vitamin D levels can be linked to miscarriage among women with prior pregnancy loss. 

Clearly, there are important reasons for ensuring adequate vitamin D consumption during pregnancy. However, Gustafsson's NTNU study shows that fewer than one in five pregnant women followed the Norwegian Directorate of Health recommendations to take vitamin D supplements during pregnancy.

Gustafsson states that this is a very worrying statistic. “I think that taking small actions can lead to better levels of vitamin D in pregnant women. We found that only 18 percent of the women in our study take the recommended daily allowance of 10 micrograms of vitamin D or a teaspoon of cod liver oil. The results would certainly have been better had more women taken supplements and eaten fish two to three times a week as recommended,” she says.

Essentially, natal nutrition is vital for maintaining the health of the mother and ensuring, to a certain extent, the future health of the child. One example of a critical nutrient that women are more active in maintaining sufficient levels in during pregnancy is folic acid. This reason for this, Gustafsson adds, is partly due to increased knowledge of folic acids beneficial effects in reducing neural tube defects. Therefore, “There are a lot of people who can help get this information out to pregnant women. GPs and midwives see women for pregnancy checks. It's also important that the information from the health authorities is communicated to the public and health personnel,” Gustafsson concludes.

By Laxmi Haigh