Figure 3: Dose-dependent effect of FSH therapy on progressive sperm motility and morphology. Treatment with FSH improved (a) the progressive sperm motility but not (b) the sperm morphology in men with idiopathic oligozoospermia compared with controls. (a) At low and high doses, FSH therapy ameliorated the progressive sperm motility; at intermediate doses, FSH administration did not increase this parameter. (b) At low doses, FSH did not improve the sperm morphology; at intermediate doses, it was ameliorated; and at high doses, the sperm morphology showed a trend toward the increase. FSH: follicle-stimulating hormone; CI: confidence interval; s.d.: standard deviation; std: standard; a–d: study subgroups; IV: Inverse Variance methods; df: degree of freedom.