Let f be a germ of complex analytic function at (Cd+1,0)
such that its zero level defines an irreducible germ of quasi-ordinary
hypersurface (S,0). We describe the motivic Igusa zeta function, the motivic
Milnor fibre and the Hodge-Steenbrink spectrum of f at 0 in terms of
topological invariants of the quasi-ordinary hypersurface (S,0)