From TMZ:
The autopsy of Whitney Houston is complete, TMZ has learned, but the results will be deferred pending a toxicology report.
According to our sources, a cause of death cannot be determined until the toxicology results … which typically takes 4-6 weeks.
As TMZ first reported … although the cause of death is unknown, it is increasingly looking like Whitney may have fallen asleep or lapsed into unconsciousness in the bathtub and drowned.