Long-term Graft Survival and Graft Function Following Pregnancy in Kidney Transplant Recipients: A Systematic Review and Meta-analysis

Abstract

Background: The incidence of pregnancy in kidney transplantation (KT) recipients is increasing. Studies report that the incidence of graft loss (GL) during pregnancy is low, but less data are available on long-term effects of pregnancy on the graft.

Methods: Therefore, we performed a meta-analysis and systematic review on GL and graft function, measured by serum creatinine (SCr), after pregnancy in KT recipients, stratified in years postpartum. Furthermore, we included studies of nulliparous KT recipients.

Results: Our search yielded 38 studies on GL and 18 studies on SCr. The pooled incidence of GL was 9.4% within 2 years after pregnancy, 9.2% within 2-5 years, 22.3% within 5-10 years, and 38.5% >10 years postpartum. In addition, our data show that, in case of graft survival, SCr remains stable over the years. Only within 2 years postpartum, Δ SCr was marginally higher (0.18 mg/dL, 95%CI [0.05-0.32], P = 0.01). Furthermore, no differences in GL were observed in 10 studies comparing GL after pregnancy with nulliparous controls. Systematic review of the literature showed that mainly prepregnancy proteinuria, hypertension, and high SCr are risk factors for GL.

Conclusions: Overall, these data show that pregnancy after KT has no effect on long-term graft survival and only a possible effect on graft function within 2 years postpartum. This might be due to publication bias. No significant differences were observed between pre- and postpartum SCr at longer follow-up intervals.

FIGURE 1.

Study selection for studies reporting postpregnancy graft function and/or postpregnancy graft loss.

FIGURE 2.

A–D, Pooled incidence of postpregnancy graft loss. A, Graft loss within 2 y postpregnancy: 9.4%, n = 1347 (range 10–1100), total graft loss n = 126 (range 0–111). B, Graft loss 2–5 y postpregnancy: 9.2%, n = 600 (range 8–139), total graft loss n = 55 (range 1–8). C, Graft loss 5–10 y postpregnancy: 22.3%, n = 395 (range 12–81), total graft loss n = 88 (range 0–18). D, Graft loss >10 y postpregnancy: 38.5%, 234 (range 18–118), total graft loss n = 90 (range 1–51).

FIGURE 3.

A–C, Pooled difference (mean difference [95% CI] in prepregnancy SCr and postpregnancy SCR (Δ SCr pre- and postpregnancy). A, Delta SCr within 2 y postpregnancy: SCr 0.18 mg/dL [0.05, 0.32], P = 0.007, n = 441. B, Δ SCr 2–5 y postpregnancy: SCr 0.17 mg/dL [–0.03, 0.37], P = 0.09, n = 175. C, Δ SCr 5–10 y postpregnancy: SCr 0.10 mg/dL [–0.12, 0.32], P = 0.38, n = 101. CI, confidence interval; SCr, serum creatinine; SD, standard deviation.