Christoph, P., Challande, P., Raio, L. and Surbek, D. 2020. High prevalence of severe vitamin D deficiency during the first trimester in pregnant women in Switzerland and its potential contributions to adverse outcomes in the pregnancy. Swiss Medical Weekly. 150, 2122 (May 2020), w20238. DOI:https://doi.org/10.4414/smw.2020.20238.