Khan N, Richter KS, Newsome TL, et al. Matched-samples comparison of intramuscular versus vaginal progesterone for luteal phase support after in vitro fertilization and embryo transfer. Fertil Steril. 2008 June 12. [epub ahead of print]

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http://download.journals.elsevierhealth.com/pdfs/journals/0015-0282/PIIS0015028208007474.pdf