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 2.0 \times 10 ^ { -16 } erg s ^ { -1 } cm ^ { -2 } 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 \dot { M } \sim 1.5 \times 10 ^ { -5 } M _ { \odot } yr ^ { -1 } 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 .