Can luteal phase estradiol levels predict the pregnancy outcome in in vitro fertilization cycles of good responders whose excess embryos yield blastocysts?

Abstract

Despite the improvements in assisted reproductive technologies, knowledge of the implantation phase of in vitro fertilization (IVF) is still sparse. There are two major determinants of implantation: embryos and the endometrium. It has been documented that blastocysts have higher implantation potentials (1). So the best approach should be the transfer of the embryos at the blastocyst stage, which seems to be more physiological. As for the second determinant, the endometrium, it has been shown that the decreased sex steroid levels after pituitary down-regulation result in lower implantation (2, 3). Together with luteal progesterone supplementation, there are various reports documenting higher luteal E2 levels in conceptive cycles (3–6).