  Searching for the presence of circumstellar material is currently the only
direct way to discriminate between the different types of possible progenitor
systems for Type Ia supernovae. We have therefore looked for narrow H-alpha in
a high-resolution spectrum of the normal Type Ia supernova 1994D taken 10 days
before maximum and only 6.5 days after explosion. We derive an upper limit of
2.0E-16 erg cm^{-2} s^{-1} for an unresolved emission line at the local H II
region velocity. To estimate the limit this puts on wind density, we have made
time-dependent photoionization calculations. Assuming spherical symmetry we
find an upper limit of the mass loss rate which is roughly 1.5E-5 solar masses
per year for a wind speed of 10 km s^{-1}. This limit can exclude only the
highest-mass-loss-rate symbiotic systems as progenitors. We discuss the effect
of asymmetry and assess the relative merits of early optical, radio and X-ray
limits in constraining mass loss from Type Ia progenitors. We find that X-ray
observations can probably provide the most useful limits on the progenitor mass
loss, while high-resolution optical spectroscopy offers our only chance of
actually identifying circumstellar hydrogen.
