Luteal Phase Defects

Luteal phase defects are of important clinical impact on our patients. This chapter provides a review about pathophysiologic aspects, diagnostic criteria, clinical consequences, and treatment options. Luteal phase defects are defined by a time lag in endometrial development. From a pathophysiologic point of view, dysfunction of the corpus luteum and decreased response of the endometrium to progesterone can be responsible. Luteal phase defects are associated with luteal infertility, recurrent implantation failure, and (recurrent) miscarriage. Notably, the majority of evidence concerning treatment deals with luteal support with gestagens. Notably, the support with vaginal micronized progesterone and, in the course of IVF, oral dydrogesterone are the most evidence-based measures. In addition, luteal support with HCG or GnRH analogues after IVF embryo transfer and the use of elective frozen embryo transfer in PCOS women with high peak estradiol have been demonstrated to increase the chance for ongoing pregnancy and/or live birth.