Immunoglobulin M nephropathy (IgMN) is a glomerular disease that may be identified in all age groups, but children and young adults appear to have been affected more frequently in some series. The clinical picture could differ from hematuria to rapidly progressive glomerulonephritis. The main characteristics in pathologic examination are mesangial hypercellularity with a diffuse and granular immunoglobulin M deposition in the glomerular structure. To date, a standardized protocol has not been proposed for IgMN treatment. Systemic corticosteroids, calcineurin inhibitors, cyclophosphamide, and rituximab were agents reported in the literature. We present a 30-year-old woman admitted to the hospital for edema in the lower extremities at the 31st week of pregnancy. She had one abortus previously, and this was her second pregnancy. Renal biopsy performed after delivery was reported as IgMN with mesangial proliferation. She received 1 mg/kg/day prednisone therapy achieving complete remission. This report is the first case of IgMN developed in pregnancy.