Source: http://www.nejm.org/doi/full/10.1056/NEJMoa1700732

Contemporary Hormonal Contraception and the Risk of Breast Cancer
Lina S. Mørch, Ph.D., Charlotte W. Skovlund, M.Sc., Philip C. Hannaford, M.D., Lisa Iversen, Ph.D., Shona Fielding, Ph.D., and Øjvind Lidegaard, D.M.Sci.
N Engl J Med 2017; 377:2228-2239December 7, 2017DOI: 10.1056/NEJMoa1700732