Recurrent implantation success in consecutive embryo transfer cycles: a unique case report.

We describe here a unique case of a woman with an azoospermic male partner conceiving each time during ten consecutive in-vitro fertilization embryo transfer (IVF-ET) cycles. A 27 year old woman reported with primary infertility to our out-patient department at the Institute of Reproductive Medicine, Salt Lake, India in November 2001. Ten consecutive IVF-ET cycles including both, fresh and frozen embryos were performed over a span of ten years. Following each ET, the woman became pregnant; however, viable babies were not achieved. Finally, after the tenth consecutive IVF-ET cycle, a caesarean section (CS) was performed at 30 weeks and twin babies weighing 1.3 kg and 1.25 kg, respectively, were delivered and both the babies survived. It seems unlikely that the woman's conception with each embryo transfer was merely coincidental; a persistently receptive window of implantation with a high embryo implantation rate is evident. This case motivated us to introduce the term, repeated implantation success (RIS). We hypothesize that for successful implantation, expression of various factors during each cycle may be possible only in genetically pre-determined women. Identification of these genetically pre-determined set of marker(s) could help in predicting the chances of a successful pregnancy in women undergoing IVF.