Summary.Using the quadratic response function at the ab initio SCF level of approximation we have calculated the relativistic corrections from the spinorbit Hamiltonian, HSO, to the indirect nuclear spinspin coupling constants of XH4 (X=C, Si, Ge, and Sn). We find that the spinorbit contributions to JXH are small, amounting only to about 1% for JSnH. For the geminal HH coupling constants the relativistic corrections are numerically smaller than for JXH, but in some cases relatively larger compared to the actual magnitude of JHH. We also investigate the use of an effective one-electron spinorbit Hamiltonian rather than the full HSO in the calculation of these corrections.