Pregnant women, in Germany, are not sufficiently supplied with Vitamin D – and not just in winter.

This is the result of a study, published in British Journal of Nutrition, by Prof. Clemens Kunz and his research group at the Institute of Nutritional Science, Justus-Liebig University Giessen (JLU); together with Dr. Peter Gilbert and his team from the St. Josefs Hospital Giessen Hospital. The research, carried out on 261 pregnant women and 328 newborns, showed that during the winter months 98 percent of the pregnant women had a Vitamin D status lower than that recommended by the German Nutrition Society (DGE). However, in the summer months when Vitamin D can be formed by sunlight in the skin, the levels were often still too low.

The DGE and other professional societies, such as The German Society of Pediatrics and Adolescent Medicine recommend 105 to 30 minutes of outdoor exposure in order to stimulate Vitamin D production in the skin. Due to the generally poor Vitamin D status of the population in Germany the DGE has recently increased the Vitamin D intake recommendations for pregnant women from 5 micrograms (200 International Units, IU) to 20 micrograms (800 IU) per day but only if no endogenous Vitamin D synthesis occurs in the skin.

In Germany, there has been no reliable data to assess the supply of Vitamin D in pregnancy because investigation on its levels in the blood is required and this research is expensive and not routinely performed.

An adequate supply of Vitamin D is important for both mother and child as many studies suggest a link between poor Vitamin D status in pregnancy and the occurrence of complications during pregnancy, which can include: diabetes mellitus, hypertension, infection and preterm birth. The risks for newborns relate to an insufficient bone structure, lung disease and also diabetes mellitus.

Due to the alarming data revealed in the Giessen study, Prof. Kunz argues for a routine examination of the Vitamin D status in pregnant woman. This should be done by measuring 25-hydroxyvitamin D in the blood, the form in which Vitamin D is stored, and the status of this is the best way to determine the presence of the vitamin. Prof. Kunz states that once the insufficiency is diagnosed pregnant women should take supplements containing Vitamin D. Furthermore, based on the results of the study, he recommends pregnant women should take these precautions particularly in the winter months.

The International Osteoporosis Foundation, the Canadian Osteoporosis Society and the Endocrine Society defines 25-hydroxyvitamin D levels of less than 50 nanomoles per liter (nmol /l) or less than 20 nanograms per milliliter (ng/ml)  as a Vitamin D deficiency. The Giessen study shows that around 50 percent of the women had a classified Vitamin D deficiency in the summer.

The most important factor influencing the Vitamin D status of the women was thought to be the time of year, as the supply of Vitamin D through diet is very low and the greater part is produced by  UV-B rays of the sun in the skin, from October to March. However, the intensity of sunlight in Germany is too weak to provide enough Vitamin D for the body. Therefore, it is necessary to increase the intake of Vitamin D via supplements. The implementation of this in everyday life is not easy, as packaging inserts in Vitamin D tablets often warns against an excessive intake while pregnant. Prof. Kunz believes that the relevant regulatory authorities need to intervene: “Without changing the rules, a better Vitamin D status and thus a lower risk for pregnant women and their children is hard to achieve. An overdose is not likely as the Vitamin D supplied, either as a tablet or produced in the skin, is not effective as such. The active form is produced by the body in the kidney – but only if there is a need and if it is not needed then Vitamin D remains inactive and is broken down and excreted “.

The research will now move on to an observation study in pregnant women that have been medically diagnosed with Vitamin D deficiency and whether the daily intake of 1,000 IU of Vitamin D during pregnancy is sufficient to ensure the required supply


Wuertz C, Gilbert P, Baier W, Kunz C (2013):
Cross-sectional study of factors did influence the 25-hydroxyvitamin D status in pregnant women and in cord blood in Germany, British Journal of Nutrition

This paper is freely available online for 2 weeks after publication via the following link



Involved in this study, gynecological surgeries are Sabine Fink, Kerstin Schröder, Klaus-Dieter Fleck, Peter Gilbert (St. Josefs Hospital, Giessen) and Prof. Dr. Dr.hc. Hans-Rudolf Tinneberg (Obstetrics and Gynecology, University Hospital Giessen and Marburg).


Prof. Dr. Clemens Kunz

E-mail: clemens.kunz(at)




Leave a reply

Your email address will not be published. Required fields are marked *