Long-Term Effects of Pregnancy on Renal Graft Function in Women After Kidney Transplantation Compared With Matched Controls

Background: An important benefit associated with kidney transplantation in women of child-bearing age is increased fertility. We retrospectively evaluated the maternal and fetal complications and evolution of graft function associated with 22 pregnancies post-kidney and kidney-pancreas transplantation, compared with controls without pregnancy post-transplantation, who were matched for gender, year of transplantation, type of donor, age at transplantation, number of transplants, type of transplant (kidney vs kidney-pancreas), and cause of native kidney failure, as well as for renal parameters including serum creatinine and urine protein excretion 1 year before delivery.

Results: The mean age at time of transplantation was 22.32 (range, 19.45-33.1) years. The mean interval between transplantation and delivery was 75.7 (range, 34-147.8) months. Main maternal complications were pre-eclampsia in 27.3%. The main fetal complications included delayed intrauterine growth (18.2%), preterm deliveries (89.4%), and one death at 3 days postdelivery. The mean serum creatinine level pre-pregnancy was 1.17 (range, 0.7-3.1) mg/dL. Graft failure was higher in the pregnancy group (6 vs 3) but did not differ statistically from the control group, and was associated with creatinine pre-pregnancy (odds ratio [OR], 1.71; 95% confidence interval [CI], 1.15-3.45; P = .04), age at transplantation (1.13 [1.03-1.21]; P = .032), and time of follow-up (2.14 [1.27-2.98]; P = .026). Delta serum creatinine was not different in both groups: 1.05 ± 0.51 versus 0.99 ± 0.92 mg/dL, study versus control group, respectively (P = .17).

Conclusion: Pregnancy after kidney transplantation is associated with serious maternal and fetal complications. We did not observe a significantly increased risk of graft loss or reduced graft function in comparison with recipients with similar clinical characteristics.