Maternal and infant outcomes of pregnancy after kidney transplantation: a retrospective cohort study

To investigate the effect of postoperative pregnancy on maternal-infant outcomes and transplanted kidney function in kidney transplantation (KT) recipients.

Our study included 104 KT recipients and 104 non-KT women who delivered at four hospitals affiliated with Zhejiang University School of Medicine from December 2015 to November 2023.

In the KT group, kidney function showed a downward trend after delivery, and most patients recovered normal kidney function within 6 months postpartum. Tacrolimus blood concentration during pregnancy averaged (6.1 ± 1.4) μg/L, increasing to (7.1 ± 2.6) μg/L on the second day after delivery, indicating an upward trend in postpartum concentrations. Compared to the non-KT group, the KT group had higher prevalences of gestational hypertension (33.7% vs. 3.3%), gestational diabetes mellitus (21.2% vs. 17.5%), intrahepatic cholestasis of pregnancy (5.8% vs. 1.7%), placental abruption (1.9% vs. 0.8%), and preterm birth rate (79.8% vs. 9.2%) but had a lower prevalence of fetal growth restriction (8.3% vs. 21.7%). Univariate analysis showed that pre-pregnancy estimated glomerular filtration rate (eGFR), penatal eGFR, gestational hypertension, and preeclampsia may influence neonatal outcomes. Binary logistic regression analysis showed that preeclampsia (odds ratio [OR] = 133.89, 95% confidence interval [CI]: 1.27-156.20, P = 0.031) and hypertension during pregnancy (OR = 5.81, 95% CI: 1.02-33.27, P = 0.048) were risk factors, and glomerular filtration rate during pregnancy (OR = 0.95, 95% CI: 0.90-0.99, P = 0.026) was a protective factor.

Although pregnancies in KT recipients are considered high-risk, the overall risks are manageable. Strengthening the management of KT recipients with reproductive intent is recommended to improve maternal and infant outcomes.