Introduction: Despite rising births in kidney transplant recipients, their babies face elevated risks, including preterm birth and low birthweight, with over 50% being preterm and experiencing worse neonatal outcomes than other preterm babies, highlighting the importance of understanding its long-term implications beyond the neonatal period. We aimed to explore the long-term health trajectories of children born to transplanted mothers compared to those of mothers who had not received kidney replacement therapy (non-KRT).
Methods: We utilised linked data between the Australia and New Zealand Dialysis and Transplant Registry, perinatal (births ≥20 weeks gestation, 1991-2013) and hospital admission datasets (available until 2018) in four jurisdictions in Australia (South Australia, Western Australia, Australian Capital Territory and New South Wales).  
Results: Of 1,865,425 babies with 6,063,327 hospital admissions, there were 137 birth admissions and 551 subsequent admissions (n=99 babies) in the transplant cohort, with a median follow-up duration of 2.5 years [IQR: 0.9-5.3] compared to 2.9 years [1.1-5.4] in the non-KRT cohort (p=0.03). Neonatal deaths (<28 days post-delivery) were 3.5% in the transplant cohort (0.2% non-KRT), with just one post-neonatal death. Children of transplanted mothers experienced lengthier birth admissions (median 6 days [IQR: 4-16]) than those of non-KRT mothers (3 days [2-5]), p<0.001. Nearly 70% of children born to transplanted mothers (vs 34% non-KRT) had perinatal-related admissions, associated with gestational age/fetal growth issues, respiratory/cardiovascular diseases, haemorrhagic/haematological conditions, endocrine/metabolic disorders, infections and pregnancy complications, 2-5 times higher than the non-KRT cohort (p<0.05) (Table 1). Subsequent admissions for respiratory, nervous system, and endocrine/metabolic diseases were also more prevalent in children of transplanted mothers (7-29%) than the non-KRT (4-24%), p<0.05. Prematurity (57% Transplant vs 8% non-KRT) and pre-eclampsia (30% Transplant vs 6% non-KRT) were further explored as crucial factors affecting neonatal health. Preterm children of transplanted mothers showed heightened respiratory-related subsequent admissions (41%) compared to other preterm children (26%, p<0.001). Among women with pregnancy-induced hypertension (including pre-eclampsia), children of transplanted mothers had higher rates of perinatal conditions (80% vs 51%), endocrine/metabolic diseases (8% vs 4%), and respiratory diseases (35% vs 23%), p<0.05.
Conclusions: This first Australian follow-up study of children of transplanted mothers revealed prolonged hospital stays and a surge of perinatal-related conditions and respiratory diseases. These findings emphasise the need for ongoing monitoring to improve the long-term health of these children.