  We show that antiferromagnetic spin-density wave order in the two-dimensional
Hubbard model yields a drop of the charge carrier density as observed in recent
transport measurements for cuprate superconductors in high magnetic fields upon
entering the pseudogap regime. The amplitude and the (generally incommensurate)
wave vector of the spin-density wave is obtained from dynamical mean-field
theory (DMFT). An extrapolation of the finite temperature results to zero
temperature yields an approximately linear doping dependence of the magnetic
gap $\Delta(p) \propto p^*-p$ in a broad doping range below the critical doping
$p^*$. The magnetic order leads to a Fermi surface reconstruction with electron
and hole pockets, where electron pockets exist only in a restricted doping
range below $p^*$. DC charge transport properties are computed by combining the
renormalized band structure as obtained from the DMFT with a doping-independent
phenomenological scattering rate. A pronounced drop of the longitudinal
conductivity and the Hall number in a narrow doping range below $p^*$ is
obtained.
