To observe the effect of coefficient of variation (CV) of calcineurin inhibitors (CNI) during pregnancy on the function of transplant kidney, pregnancy and fetus in kidney transplant recipients.

The clinical data of child-bearing period recipients getting kidney transplantation in the First Affiliated Hospital of Wenzhou Medical University from January 1, 1997 to June 30, 2019 were retrospectively analyzed, 14 recipients who had conceived naturally for 15 times were incorporated. The dosage and blood concentration of CNI, serum creatinine and estimated glomerular filtration rate were monitored monthly 3 months before and after pregnancy. The CV was calculated based on blood trough concentration of CNI. The outcome of pregnancy, fetal complications and newborns were observed, and the correlation between CV of CNI and renal function, pregnancy-related condition was analyzed.

The mean age of 14 recipients at pregnancy was (31±5) years (21-39 years), the mean transplantation-pregnancy interval was (71±43) months (22-157 months). The CNI blood concentration decreased gradually after pregnancy with a lowest level in the mid trimester of pregnancy. CV of CNI was (45±30)% during the early trimester of pregnancy, which was higher than that before pregnancy, the mid trimester and after pregnancy (P all<0.05). The mean serum creatinine decreased first and then increased during pregnancy, with the lowest level to (62±11) μmol/L in the mid trimester, which was lower than that before pregnancy (P<0.05). Asymptomatic proteinuria (urinary protein+ + ) occurred in 1 recipient during pregnancy and turned negative after delivery. Renal graft dysfunction was observed in 3 recipients (7 months, 10 months and 9 years after delivery respectively); 2 recipients were complicated with preeclampsia during pregnancy, and relieved immediately and 4 months after delivery respectively; 4 recipients with urinary system infection were relieved by urine alkalizing and increasing water intake. The mode of delivery includes 2 natural delivery and 13 cesarean section. Of the 15 neonates, 1 was low-weight, and 2 were premature at 32 weeks and 36 weeks + 4 days respectively. The incidence of renal graft dysfunction and premature birth in recipients with high CV of CNI during late trimester of pregnancy was higher than that of recipients with low CV (χ²=5.104 and 9.231, P all<0.05).

CV of CNI during early trimester of pregnancy after kidney transplantation increased significantly. Pregnant recipients after kidney transplantation with high CV of CNI were more likely to have premature birth and renal graft dysfunction.