Luteal phase support (LPS), after controlled ovarian stimulation (COS), is a routine practice in in vitro fertilization (IVF) – embryo transfer (ET) because stimulated IVF cycles are associated with a defective luteal phase in almost all patients.

The receptivity of endometrium influence the success of IVF cycles and is dependent on the hormonal status of the endometrium at the time of implantation.Although it is generally agreed that LPS in IVF cycles improves the outcome, there is controversy over the best protocol. It is well established that luteal support with progesterone improves implantation in IVF cycles. But there are controversies about adding estrogen, GnRH agonist or LH to progesterone supplementation as LPS. Various studies have been done which showed that there is no improvement in pregnancy rate by adding estrogen, GnRH agonist or LHin luteal phase.In different studies, which involved patients undergoing IVF stimulation with GnRH antagonist or agonist protocol, the addition of E2 to progesterone during the luteal phase did not result in a higher probability of pregnancy (Fatemi et al 2006, Moini A et al 2011).Ata B et al 2008 and Inamdar DB et al 2012 demonstrated that GnRH agonist administration in luteal support in the long protocol cycles does not result in an increase in ongoing pregnancy rates. One recent study showed thatluteal supplementation with rLH combined with vaginal progesterone does not appear to improve pregnancy outcomes in high responder patients undergoing long GnRH agonist IVF treatments (Seckin B et al 2014).