ObjectiveTo assess the effects of pregnancy on cyclosporine levels in six renal allograft patients.MethodsMaternal demographic, laboratory, clinical, and perinatal outcome data were recorded in six pregnant women with previous renal allograft receiving cyclosporine immunosuppression. The cyclosporine and serum creatinine levels wee measured before pregnancy, during each trimester, and postpartum.ResultsThe mean (standard deviation [SD] maternal age was 29.1 (3.8) years. Parity from 0 to 3. Mean serum creatinine levels tended to be lower during pregnancy than before or after, as did the mean cyclosporine levels. After adjusting for dose, five of six patients had declines in cyclosporine level during pregnancy. The mean (SD) gestational age at delivery was 37.5 (2.8) weeks with a mean (SD) birth weight of 2837 (538) g.ConclusionPregnancy in patients with renal allografts can lead to a substantial decline in cycloporine levels.