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 gA. This scenario corresponds to a magnetar environment. We found that gA decreases both as function of the magnetic field strength and the baryonic density. It turns out that at the nuclear density ρ0 the axial-vector coupling takes the value gA⁎≈0.92. Although gA decreases in general with the magnetic field intensity, gA⁎ does not change in a relevant way with the magnetic field.