  For the $e^+ e^- \to e^+ e^- \gamma$ process at colliding beams,
macroscopically large impact parameters give an essential contribution to the
standard cross section. These impact parameters may be much larger than the
transverse sizes of the colliding bunches. It means that the standard
calculations have to be essentially modify. In the present paper such a
beam-size or MD-effect is calculated for bremsstrahlung at B-factories PEP-II
and KEKB using the list of nominal parameters from Review of Particle Physics
(2002). We find out that this effect reduces beam losses due to bremsstrahlung
by about 20%.
