Timing of Pregnancy After Kidney Transplantation and Risk of Allograft Failure

C. Rose; J. Gill; N. Zalunardo; O. Johnston; A. Mehrotra; J. S. Gill


American Journal of Transplantation. 2016;16(8):2360-2367. 

In This Article

Abstract and Introduction


The optimal timing of pregnancy after kidney transplantation remains uncertain. We determined the risk of allograft failure among women who became pregnant within the first 3 posttransplant years. Among 21 814 women aged 15–45 years who received a first kidney-only transplant between 1990 and 2010 captured in the United States Renal Data System, n = 729 pregnancies were identified using Medicare claims. The probability of allograft failure from any cause including death (ACGL) at 1, 3, and 5 years after pregnancy was 9.6%, 25.9%, and 36.6%. In multivariate analyses, pregnancy in the first posttransplant year was associated with an increased risk of ACGL (hazard ratio [HR]: 1.18; 95% confidence interval [CI] 1.00, 1.40) and death censored graft loss (DCGL) (HR:1.25; 95% CI 1.04, 1.50), while pregnancy in the second posttransplant year was associated with an increased risk of DCGL (HR: 1.26; 95% CI 1.06, 1.50). Pregnancy in the third posttransplant year was not associated with an increased risk of ACGL or DCGL. These findings demonstrate a higher incidence of allograft failure after pregnancy than previously reported and that the increased risk of allograft failure extends to pregnancies in the second posttransplant year.


An advantage of kidney transplantation over other types of renal replacement therapies is that it may reverse the hypothalamic gonadal dysfunction found in women with renal failure, providing an opportunity for conception.[1] Despite knowledge of thousands of successful pregnancies in kidney transplant recipients,[2–9] the optimal timing of pregnancy after transplantation remains uncertain.[10,11] Existing information regarding the timing of pregnancy and the risk of graft loss is derived from voluntary data sources that may be prone to ascertainment bias,[3,4,12,13] and population-based estimates of the pregnancy-associated risk of allograft failure are not available. Current American guidelines state that conception may be considered as early as 1 year posttransplantation, while European guidelines suggest delaying pregnancy for a period of 2 years posttransplantation.[14–16] More precise information regarding the association of pregnancy at different times after transplantation with the risk of allograft failure may inform clinical decision making and help maximize the likelihood of a safe and successful pregnancy in transplant recipients. The objective of this study was to determine population-based estimates of the risk of allograft failure among women who became pregnant in the first, second, and third years after kidney transplantation, using Medicare claims to capture pregnancy events.