Luteal phase support in assisted reproduction cycles.

The aspiration of the granulosa cells that surround the oocyte and the use of gonadotropin releasing hormone agonists (GnRHa) during assisted reproduction technology (ART) treatment can interfere with the production, during the luteal phase, of progesterone, which is necessary for successful implantation of the embryo. Providing hormonal supplementation during the luteal phase with either progesterone itself, or human chorionic gonadotropin (hCG), which stimulates progesterone production, may improve implantation and, thus, pregnancy rates.