Impact of Pregnancy on GFR Decline and Kidney Histology in Kidney Transplant Recipients

Introduction: Women with advanced kidney disease are advised to wait until after transplant to pursue pregnancy, but the impact of pregnancy on estimated glomerular filtration rate (eGFR) decline and kidney histology is unclear. Methods: We identified a cohort of women aged 18 to 44 years at transplant from 1996 to 2014 at our 3-site program (N = 816) and determined whether they had a pregnancy >20 weeks gestation post-transplant by chart review. Outcomes included rate of change in eGFR after pregnancy, changes in kidney histology before and after pregnancy, graft failure, and 50% reduction in eGFR. Results: There were 37 women with one or more pregnancies lasting longer than 20 weeks gestation post-transplant. Comparing women with and without pregnancy post-transplant, there was a significant increase in the rate of eGFR decline after pregnancy (−2.4 ml/min per 1.73 m² per year vs. −1.9 ml/min per 1.73 m² per year in women with no pregnancy, P < 0.001). Pregnancy did not affect the risk of graft failure, death-censored graft failure, or 50% reduction in eGFR. Conclusion: Pregnancy affects the rate of eGFR decline in the allograft. Postpregnancy biopsy findings revealed an increase in vascular injury, which could be a potential mechanism. We did not find a significant increase in risk of graft failure or reduction in eGFR by 50% owing to pregnancy.