  Using appropriate QCD finite energy sum rules, we discuss the influence of an
external magnetic field and baryonic density on the axial-vector coupling
constant $g_{A}$. This scenario corresponds to a magnetar environment. We found
that $g_{A}$ decreases both as function of the magnetic field strength and the
baryonic density. It turns out that at the nuclear density $\rho _{0}$ the
axial-vector coupling takes the value $g_{A}^{*} \approx 0.92$. Although
$g_{A}$ decreases in general with the magnetic field intensity, $g_{A}^{*}$
does not change in a relevant way with the magnetic field.
