  Abundances of light nuclei formed during primordial nucleosynthesis are
predicted by Standard Big Bang Model. The latest data from WMAP, with
precision's higher than ever before, provides a motivation to determine
theoretical higher order corrections to change in helium abundance and the
related parameters. Here we evaluate the QED corrections to the change in these
parameters during primordial nucleosynthesis using finite temperature effects
at the two loop level. Relative variations in neutron decay rate, total energy
density of the universe, relative change in neutrino temperature etc., with two
loop corrections to electron mass, at the timescale when QED corrections were
relevant, have been estimated.
