Pregnancy after kidney transplantation: 40 years single-center experience

Background: Kidney transplantation (KT) improves quality of life, including fertility recovery. Objective: to describe outcomes of post-KT pregnancy and long-term patient and graft survival compared to a matched control group of female KT recipients who did not conceive. Methods: retrospective single -center case-control study with female KT recipients from 1977 to 2016, followed-up until 2019. Results: there were 1,253 female KT patients of childbearing age in the study period: 78 (6.2%) pregnant women (cases), with a total of 97 gestations. The median time from KT to conception was 53.0 (21.5 - 91.0) months. Abortion rate was 41% (spontaneous 21.6%, therapeutic 19.6%), preterm delivery, 32%, and at term delivery, 24%. Pre-eclampsia (PE) occurred in 42% of pregnancies that reached at least 20 weeks. The presence of 2 or more risk factors for poor pregnancy outcomes was significantly associated with abortions [OR 3.33 (95%CI 1.43 - 7.75), p = 0.007] and with kidney graft loss in 2 years. The matched control group of 78 female KT patients was comparable on baseline creatinine [1.2 (1.0 - 1.5) mg/dL in both groups, p = 0.95] and urine protein-to-creatinine ratio (UPCR) [0.27 (0.15 - 0.44) vs. 0.24 (0.02 - 0.30), p = 0.06]. Graft survival was higher in cases than in controls in 5 years (85.6% vs 71.5%, p = 0.012) and 10 years (71.9% vs 55.0%, p = 0.012) of follow-up. Conclusion: pregnancy can be successful after KT, but there are high rates of abortions and preterm deliveries. Pre-conception counseling is necessary, and should include ethical aspects.