Foetal serum but not urinary β2-microglobulin correlates with histological injury to the kidney

In a context of foetal obstructive uropathies, biochemical markers can be helpful to assess the renal function, but most studies to date have focused on their correlation with ultrasound findings and neonatal outcome. Our aim was to evaluate foetal β2-microglobulin as an index of histological injury to the kidney. β2-microglobulin was measured in serum and/or urine from 27 foetuses with bilateral obstructive uropathy, and compared to the findings of kidney examination following the termination of pregnancy. In serum, increased β2-microglobulin levels correlated to a decreased number of glomeruli, a reduction in the blastema and the presence of primitive ducts reflecting renal hypoplasia and dysplasia. However, elevated β2-microglobulin levels in the urine correlated only to a decreased number of glomeruli.