This particular medication has been discontinued by its manufacturer.
Tri-Previfem was a generic version of Ortho Tri-Cyclen®, and other generic versions are still available (sold under the names Tri-Sprintec® and TriNessa®).
This medication was likely discontinued because its manufacturer (Teva Pharmaceuticals USA) "bought out" the maker of Tri-Sprintec (Barr Pharmaceuticals, Inc.), and it did not make sense for Teva to be making two different generic versions of Ortho Tri-Cyclen.
In addition to its use for birth control, Tri-Previfem is approved to treat acne.