RETRACTED: Effect of metformin pretreatment on pregnancy outcome of in vitro matured oocytes retrieved from women with polycystic ovary syndrome

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).The article is a duplicate of a paper that has already been published in the Chinese Journal of Practical Gynecology and Obstetrics. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper is not under consideration for publication elsewhere or previously published, even in a language other than English. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.