Liao S, et al. - In a nested case-control study, cases of otosclerosis (n = 22) and age, ethnicity-matched controls (n = 22) were chosen to examine the potential role of maternal serum concentrations of placental growth hormone variant (GH-V), insulin-like growth factor (IGF) 1 and 2, and IGF binding proteins (IGFBP) 1 and 3 in pregnancies complicated by otosclerosis. By enzyme-linked immunosorbent assay, maternal serum hormone concentrations at 26 and 34 weeks of gestation were determined. In the otosclerosis group, maternal serum GH-V concentrations were significantly increased at 26 and 34 weeks of gestation vs the control group. Findings revealed that maternal serum IGF-1 concentrations in otosclerotic patients at 34 weeks were significantly higher than in the controls. In pregnancy complicated by otosclerosis, maternal serum concentrations of GH-V and IGF-1 have been altered, suggesting that the GH-IGF axis may contribute to the development of this condition during pregnancy. At 26 weeks gestation, the rise in IGF-1 was not noted.