Intravenous immunoglobulin (IVIG) is a fractionated blood product made from pooled human plasma that is used to treat a number of medical disorders.1–3 In past years, several authors have proposed using IVIG to treat obstetric conditions such as recurrent miscarriage that are associated with an autoimmune aetiology. Indeed, because its precise mechanism of action has not been well elucidated, IVIG has been described as a non-specific immune suppressant in many complex immunological diseases. Various investigators have documented targeted immunological effects such as the suppression and neutralisation of autoantibodies, a reduction on natural killer cell activity, modification of cytokine production, inhibition of complement binding and activation and inhibition of superantigens among its many plausible effects on immune function.4,5 The US Food and Drug Administration has approved the use of IVIG as a first-line therapy for autoimmune thrombocytopenia, while other conditions such as recurrent spontaneous miscarriage (both primary and secondary), antiphospholipid antibody syndrome and repeated unexplained in vitro fertilisation failure remain off-label indications for this blood product. The high cost of IVIG must be considered in the context of evaluating its role as a first-line therapy. The British Columbia Provincial Blood Coordinating Office indicated that a single course of treatment for an adult commonly exceeds $10 000.1 They also noted that significant and steady increases in Canada’s budget for IVIG paid for by provincial and territorial governments has risen over 30% each year, with a projected 2000–2001 spending of more than $160 million.6 Furthermore, because it is a blood product isolated from large pools of human plasma, there is a theoretical risk of introducing transmissible agents to women receiving treatment with IVIG. Given the prior use of IVIG for treatment of recurrent miscarriage and questions regarding its degree of efficacy, we conducted a systematic review of randomised controlled trials that compared the use of IVIG with other therapies for this condition.