[en] The problem of stable-state determination is considered in unified gauge theories involving gravitation. The gravitational fields are examined at a classical level. The self-consistent set of field equations is studied in the semiclassical approach. A new determination of stable states is given. If the conditions of the determination are not satisfied then the vacuum state may be metastable. For the case of axial symmetry the metastable Z-type states are shown to cancel if these states are symmetric. (author)