Process for preparing polyether alcohols with DMC catalysts using compounds bearing SiH groups as additives

Process for preparing polyether alcohols with elevated polydispersity by polymerization by means of double metal cyanide catalysts (DMC catalysts), characterized in that, before or during the polymerization, one or more additives, optionally mixed, consisting of compounds having one or more hydrogen atoms bonded to one silicon atom as Si—H additive are added to the starting reaction mixture comprising the OH-functional starting compound and the DMC catalyst.