Coasting Versus Antagonist Protocol in Patients at High Risk of OHSS

Infertility affects up to one in seven couples all over the world. In vitro fertilization-embryo transfer (IVF-ET) and intracytoplasmic sperm injection (ICSI) are commonly used in the management of infertility attributable to tubal factor, significant endometriosis, male factor and also persistent unexplained infertility. Recruitment and development of multiple follicles in response to gonadotrophin stimulation are necessary for successful assisted reproduction. In young ovulating women undergoing IVF treatment, the standard stimulation protocol can result in either poor response or ovarian hyperstimulation syndrome (OHSS). OHSS is a serious and potentially life-threatening iatrogenic complication of controlled ovarian hyperstimulation (COH) which may cause serious impact on patient's health. OHSS is the most feared complication of IVF-related ovarian stimulation, which in its severe form leads to hospitalization and in the worst case scenario fatal complications. As many as 33% of IVF cycles have been reported to be associated with mild forms of OHSS. The incidence of moderate OHSS is estimated to be between 3% and 6%, while the severe form may occur in 0.1-3% of all cycles. Among high risk women the incidence approaches 20%. Development of multiple follicles forms the basis of OHSS. Exogenous human chorionic gonadotrophin (hCG) administration for the final maturation of oocytes or endogenous production of hCG after pregnancy is the second factor needed for the development of severe OHSS. Severe OHSS is characterized by massive ovarian enlargement, pleural effusion, ascites, oliguria, hemoconcentration, and thromboembolic phenomena. Coasting is described as a withholding therapy while continuing with releasing hormone agonist/antagonist administration, until safe levels of estradiol (E2) are attained. GnRH antagonists causes an immediate suppression of E2 levels and therefore could prevent OHSS in GnRH antagonist cycles. A comparison between coasting and GnRH antagonist administration in women at high risk of OHSS during ovarian stimulation for IVF with GnRH agonist long protocol, in the hope of preventing the drawbacks of prolonged coasting.