Inflation is currently the leading paradigm describing the physical conditions that prevail in the very early universe. During this epoch, quantum fluctuations are extracted out of the vacuum and amplified to cosmological perturbations at astronomical scales, later seeded CMB anisotropies and large-scale structures. As inflation proceeds, this inflow of super-horizon perturbations may impact on the large-scale dynamics of the universe, potentially perturbing the inflationary trajectory.