  The LISA mission will observe gravitational waves emitted from tens of
thousands of galactic binaries, in particular white dwarf binary systems. These
objects are known to have intense magnetic fields. However, these fields are
usually not considered as their influence on the orbital and rotational motion
of the binary is assumed for being too weak. It turns out that magnetic fields
modify the orbits, in particular their geometry with respect to the observer.
In this work, we revisit the issue, assuming magnetostatic approximation, and
we show how the magnetic fields within a binary system generate a secular drift
in the argument of the periastron, leading then, to modifications of the
gravitational waveforms that are potentially detectable by LISA.
