Cetrotide Treatment Optimization

Rationale: In daily practice fertility treatment is increasingly patient focused and innovative medication and standardized treatment guidelines are being developed to improve patient convenience. GnRH antagonist cotreatment to prevent premature luteinization during ovarian stimulation for IVF and ICSI greatly reduces the burden of treatment, partly by reducing the number of injections by around 21 compared with the optimal GnRH agonist 'long' protocol. However, the optimal GnRH antagonist protocol is still not known. There are a number of reasons to suggest that both the simplicity of treatment and clinical outcomes could be further improved by commencing GnRH antagonist treatment on the same day on which ovarian stimulation is started. These include more synchronized follicle development and reduced rates of premature luteinization. This study will investigate whether a novel early fixed start protocol improves outcomes in comparison to the widely employed late fixed start protocol. Objective: To demonstrate whether an early fixed start antagonist protocol improves the live birth rate compared with a late fixed start antagonist protocol by 5%. Study design: Prospective, multicenter, investigator sponsored, randomized controlled trial Study population: * Normo-ovulatory women \< 39 years with an indication for IVF or ICSI * No more than 2 previous unsuccessful IVF/ICSI cycles * BMI ≤ 32 kg/m2 Intervention: Two different GnRH antagonist treatment protocols used in daily practice will be compared. Patients will be randomized to receive one of the following two treatments: * Early fixed start: start GnRH antagonist treatment with Cetrotide 0.25 mg on the same day as FSH, cycle day 2. * Late fixed start: FSH will be administered from cycle day 2. GnRH antagonist treatment with Cetrotide 0.25 mg will commence on cycle day 6. Main study parameters/endpoints: The primary endpoint is the live birth rate per started cycle. A secondary endpoint is the number of