Pregnancy outcomes post-kidney transplantation across 23 years

Aust N Z J Obstet Gynaecol. 2024 Jan 8. doi: 10.1111/ajo.13786. Online ahead of print.

Abstract

Background: Pregnancy in kidney transplant recipients has become increasingly common. However, pregnancy carries higher risks to these patients compared to the general population.

Aims: To describe pregnancy outcomes in kidney transplant recipients.

Materials and methods: We conducted a single-centre retrospective cohort study of kidney transplant recipients who delivered after 20 weeks gestation at a quaternary hospital in Victoria, Australia, between 2000 and 2022 inclusive.

Results: The study included 37 pregnancies from 27 patients, accounting for 38 infants. Over half of recorded pregnancies occurred in the past five years (56.8%, n = 21). There were high rates of pre-existing hypertension (75.7%, n = 28). Pregnancy-induced hypertension and pre-eclampsia were common antenatal complications (21.6%, n = 8 and 48.6%, n = 18 respectively). Soluble fms-like tyrosine kinase-1 / placental growth factor ratios were elevated in all patients who developed severe pre-eclampsia (16.2%, n = 6). The median gestational age at birth was 36.4 weeks (range 20-40.4, Q1 32.9, Q3 37.6) and 59.5% (n = 22) of births were preterm. Unplanned caesarean without labour was the most common mode of birth (35.1%, n = 13). The overall caesarean rate was 62.1% (n = 23). Post-partum haemorrhage complicated over half of pregnancies (56.8%, n = 21). Fifty percent (n = 19) of infants were admitted for neonatal care, in particular neonatal intensive care, and had low birthweights under 2500 g. While there was a transient deterioration in kidney function, there was no graft rejection within one year of birth.

Conclusions: Clinicians should consider the high rates of pre-existing hypertension, preterm birth, and caesarean birth when counselling and managing pregnant kidney transplant recipients.

Keywords: kidney transplantation; pregnancy; pregnancy outcomes; renal transplantation.