What is the optimal luteal support in assisted reproductive technology?

The need for luteal phase support in IVF/ICSI is well established. A large effort has been made in the attempt to identify the optimal type, start, route, dosage and duration of luteal phase support for IVF/ICSI and frozen embryo transfer. These questions are further complicated by the different types of stimulation protocols and ovulation triggers used in ART. The aim of this review is to supply a comprehensive overview of the available types of luteal phase support, and the indications for their use.A review of the literature was carried out in the effort to find the optimal luteal phase support regimen with regards to pregnancy related outcomes and short and long term safety.The results demonstrate that vaginal, intramuscular, subcutaneous and rectal progesterone are equally effective as luteal phase support in IVF/ICSI. GnRH agonists and oral dydrogesterone are new and promising treatment modalities but more research is needed. hCG and estradiol are not recommended for luteal phase support. More research is needed to establish the most optimal luteal phase support in frozen embryo transfer cycles, but progesterone has been shown to improve live birth rate in some studies. Luteal phase support should be commenced between the evening of the day of oocyte retrieval, and day three after oocyte retrieval and it should be continued at least until the day of positive pregnancy test.So, in conclusion still more large and well-designed RCT's are needed to establish the most optimal luteal phase support in each stimulation protocol, and especially in frozen embryo transfer.