  The theoretical and observed populations of pre-cataclysmic variables
(pre-CVs) are dominated by systems with low-mass white dwarfs (WDs), while the
WD masses in CVs are typically high. In addition, the space density of CVs is
found to be significantly lower than theoretical models. We investigate the
influence of nova outbursts on the formation and (initial) evolution of CVs. In
particular, we calculate the stability of the mass transfer in case all the
material accreted on the WD is lost in classical novae, and part of the energy
to eject the material comes from a common-envelope like interaction with the
companion. In addition, we study the effect of an asymmetry in the mass
ejection, that may lead to small eccentricities in the orbit. We find that a
common-envelope like ejection significantly decreases the stability of the mass
transfer, in particular for low-mass WD. Similarly, the influence of asymmetric
mass loss can be important for short-period systems and even more so for
low-mass WD, but likely disappears long before the next nova outburst due to
orbital circularization. In both cases the mass-transfer rates increase, which
may lead to observable (and perhaps already observed) consequences for systems
that do survive to become CVs. However, a more detailed investigation of the
interaction between nova ejecta and the companion and the evolution of slightly
eccentric CVs is needed before definite conclusions can be drawn.
