Material & Methods
A PubMed search (data locking point 27 August 2012) was performed with the following search terms: levonorgestrel-releasing or Mirena® (Bayer, Leverkusen, Germany) or intrauterine system with the following limits 'English language only and published within the last 5 years'. This resulted in 629 articles, which were manually searched by the authors; the most relevant articles were included by joint decision. Studies not relating to humans were excluded. Furthermore, case reports or small case series were not included in the review as they were not considered to represent robust evidence.
Expert Rev of Obstet Gynecol. 2013;8(3):235-247. © 2013 Expert Reviews Ltd.