Immunological disturbances play a role in the majority of patients with recurrent miscarriage (RM) and therefore treatment with intravenous immunoglobulin (IvIg) has been tested in patients with RM in several trials. Seven placebo-controlled trials that were extremely heterogeneous with respect to patient characteristics and treatment procedures were carried out. One trial found that IvIg significantly improved pregnancy outcome in all patients whereas the remaining trials could either detect no treatment effect at all or only an effect in subsets of patients. In a meta-analysis, the pooled odds ratio for a new live birth in IvIg- versus placebo-treated patients with RM after a birth (secondary RM) was 1.60 (95% CI = 0.70-3.66). IvIg seems to be efficacious in patients with repeated second trimester intrauterine fetal deaths since it significantly (p < 0.01) increased the live birth rate in this subset compared with placebo. In most trials the design was suboptimal with regard to detecting any treatment effect of IvIg in RM due to low doses or starting the treatment late. A new large placebo-controlled trial should be conducted in RM patients with secondary RM or repeated second trimester fetal deaths and sufficient IvIg doses should be given with optimal timing.