Effect of pregnancy on long-term kidney function in renal transplant recipients treated with cyclosporine and with azathioprine.

In order to investigate the effect of different immunosuppressive regimens and the time interval between transplantation and pregnancy on long-term outcome, we performed a case-control study in pregnant renal allograft recipients. Eighty-one pregnancies of kidney transplanted recipients were identified [cyclosporine (CYA): n = 40; azathioprine (AZA): n = 41]. Controls were matched with respect to important prognostic factors. Posttransplant follow-up was 91.3 +/- 5 months. Graft and patient survival were similar in both groups and there was no apparent effect of immunosuppression. A total of 28 recipients (33%) delivered within 2 years and 6 (8%) subjects within 1 year after transplantation, but these short transplantation-to-pregnancy intervals had no apparent adverse effect on long-term outcome. In contrast to AZA-treated patients, CYA-treated patients experienced an increase in serum creatinine postpartum (1.15 +/- 0.2 mg/dL vs. 1.61 +/- 0.1 mg/dL; p < 0.05). Whole blood CYA levels decreased transiently during pregnancy from 115.9 +/- 8 ng/mL to 80.7 +/- 7 ng/mL leading to a gradual increase in drug dose from 240 +/- 14 mg/day to 324 +/- 21 mg/day (p < 0.05). Following delivery, there was an increase in CYA concentrations to 173 +/- 5.4 ng/mL, requiring rapid dose tapering to baseline of 246 +/- 15 mg/day. Pregnancies in renal recipients do not affect long-term patient and graft survival, independent of the immunosuppression. No detrimental effect of short transplantation-to-pregnancy intervals on long-term graft function was detected.