Labor and Delivery Outcomes in Australian Mothers after Kidney Transplantation

Key Points Women with kidney transplantation had higher rates of cesarean sections, deliveries without labor, and vaginal delivery complications. Women with a kidney transplant had more cesarean sections, even after accounting for maternal factors, preterm delivery, and past cesarean sections. Hypertensive disorders of pregnancy and breech presentation were the main drivers of planned cesarean section delivery among transplant recipients. Background Factors influencing high cesarean section rates among mothers with a kidney transplant remain unclear. Methods Using linked Australia and New Zealand Dialysis and Transplant Registry (1970–2016) and perinatal datasets (1991–2013), we compared deliveries of women with a functioning kidney transplant with those without KRT (non-KRT). Results Of 2,946,851 babies (1,627,408 mothers), 211 were born to 137 mothers with a kidney transplant. Overall cesarean section rates were twice more frequent in the transplant cohort (63% versus 26% non-KRT; P < 0.001) across all gestational periods compared with the non-KRT cohort and highest in preterm births (≥37 weeks, 48% versus 25%; P < 0.001, 33–36 weeks, 77% versus 40%; P < 0.001, and <33 weeks, 75% versus 41%; P < 0.001). Cesarean section rates remained higher after adjusting for maternal factors (incidence rate ratio, 1.5; 95% confidence interval, 1.3 to 1.7). In women with a kidney transplant with past pregnancy, 53% with no previous cesarean sections had a cesarean section in the current pregnancy (versus 19% non-KRT; P < 0.001). Mothers with a kidney transplant had less spontaneous labor (30% versus 63%; P < 0.001) and more planned deliveries (induced or elective cesarean sections; 70% versus 36%; P < 0.001) than non-KRT mothers. Nearly half of the women with transplantation (45%) delivered by nonlabor cesarean sections, mostly occurring preterm (<37 weeks, 70% versus ≥37 weeks, 30%; P = 0.002). In the transplant cohort, the main indications for nonlabor cesarean sections were hypertensive disorders of pregnancy and breech presentation (>50% versus 18% non-KRT cohort; P < 0.001) and were linked to gestational age. Nonlabor cesarean sections for fetal distress were higher in women with transplantation (10% versus 4% non-KRT; P = 0.03). In the non-KRT cohort, previous cesarean sections were the main indication for nonlabor cesarean sections (40% versus 24% transplant; P = 0.06). Postpartum hemorrhage (13% versus 7% non-KRT; P = 0.003) and fetal distress (18% versus 10% non-KRT; P = 0.001) were higher among the transplant cohort. Conclusions Women with a kidney transplant have higher rates of cesarean section delivery even after accounting for maternal factors, preterm delivery, and past cesarean sections compared with non-KRT cohorts.