Background: Poor response to ovarian stimulation with exogenous gonadotrophins occurs in 9-24% of women undergoing in vitro fertilisation (IVF) treatment, which represents an estimated 4000-10,000 women per year in the UK. Poor responders often have their treatment cycle cancelled because of expected poor outcome.One treatment strategy that may influence outcome is the choice of pituitary suppression regimen prior to the initiation of ovarian stimulation. The three commonly used pituitary suppression regimens in IVF treatment are:(1) the GnRH agonist long regimen,(2) the GnRH agonist short regimen and(3) the GnRH antagonist regimen.A systematic review of randomised controlled trials of these pituitary suppression regimens has shown the evidence to be either inconclusive or inconsistent. We therefore designed a three arm randomised trial to evaluate the effectiveness of these regimens in women who had poor ovarian response in a previous IVF treatment cycle.
Methods/design: Consenting, eligible women will be randomised to one of the three regimens using an internet-based trial management programme that ensures allocation concealment and employs block randomisation and minimisation for prognostic variables. The primary outcome is the number of oocytes retrieved. Other outcomes include total dose of follicle stimulating hormone (FSH) used for ovarian stimulation, mature oocytes retrieved, embryos available for transfer, implantation rate and clinical pregnancy rate.The sample size for this trial has been estimated as 102 participants with 34 participants in each of the three arms. Appropriate interim analysis will be conducted by a Data Monitoring and Ethics Committee (DMEC), and the final analysis will be by intention to treat.
Trial registration: ISRCTN27044628.