Women with rheumatic diseases frequently need treatment throughout pregnancy and lactation. Physicians must confront the dual challenge of monitoring the possible effects of the underlying maternal disease and the medications on both mother and child. It is essential that the maternal disease be well controlled before, during, and after pregnancy to ensure the best possible outcome for the mother and child. Corticosteroids have been used extensively and safely in pregnant patients with systemic lupus erythematosus and rheumatoid arthritis; there have been no reports of congenital malformations in the exposed infants. There is considerable experience using azathioprine during pregnancy if the maternal condition requires use of a cytotoxic drug; there has been no increased risk of congenital malformations in the exposed infants. There is limited information on the safety of other medications, including 6-mercaptopurine, cyclophosphamide, and cyclosporine. Methotrexate is contraindicated during pregnancy, and chlorambucil should be avoided because there are other effective immunosuppressive agents available for use. Corticosteroids (prednisone and methylprednisolone) can be used safely during lactation. All other immunosuppressive medications, azathioprine and 6-mercaptopurine, chlorambucil, cyclophosphamide, cyclosporine, and methotrexate, are contraindicated during lactation.