Granulocyte-colony stimulating factor (G-CSF) significantly improves inadequate endometrium

During in vitro fertilization (IVF) cycles, treatment with a medication called granulocyte-colony stimulating factor (G-CSF) significantly improves inadequate endometrium (lining of the uterus), according to a report published electronically on February 15 in Fertility and Sterility - the official journal of the American Society for Reproductive Medicine (ASRM). The reported case series also suggests that G-CSF treatment may, in general, improve IVF pregnancy chances.

G-CSF is a cytokine (protein molecules that facilitate communication between cells) that has already been FDA approved for other clinical indications.

Researchers from New York City-based Center for Human Reproduction (CHR) and a second NY fertility center reported on four women with highly inadequate endometrium, unresponsive to conventional treatments and facing IVF cycle cancellation. In all four cases, endometrial perfusion of G-CSF expanded the endometrium to a minimal thickness of 7mm within approximately 48 hours, allowing for embryo transfer. Surprisingly, all four patients also conceived.

In approximately 1% of all IVF cycles, the endometrium stays too thin for embryos to successfully implant, even with treatment. In such IVF cycles, patients and physicians face two poor options: they either accept lower pregnancy chances and transfer embryos despite inadequate endometrium, or they can cancel the embryo transfer and freeze all embryos in hope of better future cycles. Unfortunately, women with inadequate endometrium often show inadequate endometrium again in future cycles. This situation was demonstrated by two patients in this reported case series with histories of repeat IVF failures due to thin endometrium.

"Conventional treatments for inadequate endometrium have had spotty success at best. Without G-CSF perfusion, these patients, likely, would not have reached embryo transfer," explains David Barad, MD, Director of Clinical ART at CHR and one of the senior authors of the report. "That all of them also conceived was a big surprise, and is, of course, quite remarkable."

"The efficacy of G-CSF in improving endometrium, and possibly pregnancy rates in general, still needs to be confirmed in randomized controlled trials," adds Norbert Gleicher, MD, lead author of the report and Medical Director of CHR. "Indeed, we already started two such trials to test both hypotheses; but until first results become available later in 2011, we caution against over-interpreting results of this small pilot study."