Three different cases of magnetic field induced reentrant ground states in heavy fermion systems URhGe, UGe2 and CeRhIn5, recently studied in Grenoble, are discussed. URhGe is a ferromagnetic superconductor with the reentrace of superconductivity under magnetic field (H) which is associated to a spin reorientation. In the ferromagnetic superconductor UGe2 an enhancement of the superconducting upper critical field Hc2 appears at its metamagnetic transition between two ferromagnetic phases. CeRhIn 5 is a superconductor under high pressure and reentrance of antiferromagnetism is induced by magnetic field. We analyze the links between the H enhancement of the different contributions to the effective mass and the field reentrant phase.