Immunoglobulin G4 deficiency can be a new entity for primary recurrent miscarriage: Successful pregnancy in two cases after treatment with intravenous immunoglobulin

Recurrent miscarriage is one of the complications of pregnancy in which the potential role of immunologic factors has already been mentioned. Here, two young women with recurrent miscarriage were consulted in the infertility center. The diagnosis of immunoglobulin G4 (IgG4) deficiency was made through the reduction of IgG4 Ig levels and normal total IgG titer. Considering this abnormality, intravenous Ig 200 mg/kg was started monthly, and they both had successful pregnancies. Little is known about IgG4 deficiency in women with recurrent miscarriage. IgG4 deficiency should be taken into account in these patients. It is expected that these results will shed further light on the feasibility of intravenous Ig for women with recurrent miscarriage.