Background: The late impact of in utero exposure to cyclosporin A (CyA) on renal function (RF) of children more than 1 year of age has not yet been explored.

Patients: 6 children (4 girls, 2 twins) at a mean age of 2.3 years [1.3-4.5] years.

Measurements: Glomerular filtration rate (GFR) was assessed by Cin (ml/min/1.73 m2) and renal plasmatic flow (RPF) by PAH clearance. RF investigation also included uric acid clearance (Cua), electrolytes blood level and reabsorption rate, calcium: creatinine (mmol/mmol) ratio, and urinary osmolality after water restriction (mosm/kg).

Results: Both average and individual GFR were normal(122±20, mean±SD), RPF was in the lower normal range(551±95) with respect to age. Filtration fraction (GFR: RPF ratio 0.22±0.03) and Cua (0.32±0.20) were moderately elevated. Electrolytes blood level and reabsorption rate were normal. Calcium: creatinin ratio was slightly elevated in 2 children (> 0.5).

Conclusion: Children who experienced fetal exposure to maternal treatment with cyclosporine A, exhibit both a normal glomerular filtration rate and normal tubular functions assessed by methods of reference i.e. inulin and PAH clearances, after 1.3 year of age.