Pregnancy outcomes and impact of pregnancy on graft function in women after kidney transplantation

Background: Kidney transplantation facilitates pregnancy in women with end-stage kidney disease; however, the impact of pregnancy on short and longer-term graft function is uncertain.

Methods: Obstetric, fetal, and graft outcomes for pregnancies from a large Australian transplant unit (1976-2015) were reviewed. 

Results: There were 56 pregnancies in 35 women with mean age at conception 30.4 ± 0.6 years and mean transplant-pregnancy interval 5.5 ± 0.5 years. The live birth rate was 78.9%. Preterm birth (<37 weeks) occurred in 56.5%. Hypertensive disorders affected 76% of women (pre-eclampsia in 30%). Median prepregnancy serum creatinine (SCr) was 100 μmol/L (interquartile range (IQR), 80, 114 μmol/L). One-third had deterioration in graft dysfunction during pregnancy; of these, 63.2% did not return to baseline. At 2 years post-partum, median SCr was 96.4 μmol/L (IQR, 81.5-124.3). Women with prepregnancy SCr > 110 μmol/L had increased risk of pre-eclampsia (OR 4.4; 95% CI 1.2-16.8; P =.03), but not preterm birth (OR 5.4; 95% CI 0.5-53; P =.04) or low birth-weight babies (OR 1.2; 95% CI 0.5-2.9; P =.04). Women with SCr > 140 μmol/L preconception had worst SCr trajectory, including higher rates of graft loss. 

Conclusions: Kidney transplantation pregnancies remain at high risk of obstetric complications, particularly pre-eclampsia. Prepregnancy graft function can be used to predict risk of adverse pregnancy outcomes and deterioration in graft function during and after delivery.