We suggest that neutron stars experienced at birth three related physical changes, which may originate in magneto-rotational instabilities: (i) an increase in period from the initial value P0 to the current value Ps, implying a change of rotational energy Δ Erot; (ii) an exponential decay of its magnetic field from the initial value B0 to the current surface value Bs, implying a change of radiative energy Δ Erad; and (iii) an increase of space velocity from the initial value v0 to the current value v, implying a change of kinetic energy Δ Ekin. These changes are assumed to be connected by Δ Erad + Δ Ekin = Δ Erot. This means that the radiation loss and increase of kinetic energy are both at the expense of a rotational energy loss. It is shown that this energy conversion occurs during times of order of 10−4 s if the neutron stars are born with magnetic fields in the range of 1015–1016 G and initial periods in range 1–20 ms. It is shown that the birth accelerations of neutron stars are of the order of 108g.