The investigators want to test whether infusions of intravenous immunoglobulin - a blood product known to modify immune responses - in early pregnancy will increase the chance of a subsequent live birth in women with three or more miscarriages after a birth and a total of at least four miscarriages. This will be done in a trial where 82 patients will be randomly allocated to infusions with intravenous immunoglobulin or placebo during pregnancy.