Lack of effect of pregnancy on renal allograft survival or function.

To determine whether pregnancy had a long-term influence on the survival or function of renal allografts, a case-control study was conducted. Patients were selected from a pool of 915 patients transplanted at the University of Cincinnati from 1967 to 1990. The pregnancy group consisted of 18 women who became pregnant 3 months to 17 years after transplantation and who elected to continue pregnancy. There were 26 nonpregnant female controls, and 23 male control renal transplant recipients. Matching criteria were cause of end-stage renal disease (ESRD), donor source, age at transplantation, calendar year of transplantation, time from transplantation to pregnancy, and serum creatinine concentration at the time corresponding to conception. Matching was performed by one investigator, who had no knowledge of long-term outcome in any of the patients. The three groups were well-matched with regard to these criteria. Male controls had higher baseline creatinine clearances than pregnancy cases or female controls. During pregnancy, serum creatinine levels fell by 20%, and creatinine clearance rose by 53%. Immediately after pregnancy, these values returned to baseline. Graft survival, with a mean posttransplant follow-up of 11-12 years, was 77.8% in the pregnancy cases, 69.2% in the female controls, and 69.6% in the male controls. By life-table analysis, none of these differences was significant. Among surviving grafts, serum creatinine levels and creatinine clearances remained stable throughout the follow-up period. In this study, using well-matched male and nonpregnant female cohorts for comparison, pregnancy did not have an adverse long-term effect on renal allograft function or survival.