Lehigh County District Attorney James Martin made the announcement in court Friday.
Authorities say 30-year-old David Rapoport of Upper Gwynedd Township shot and killed 27-year-old Jennifer Snyder. Her body was found March 18 in a wooded ravine in the Trexler Nature Preserve near Allentown.
Rapoport entered a not-guilty plea at the arraignment.
Rapoport is charged with first-degree murder in the death of Snyder and their unborn child. The Morning Call of Allentown reports that he told the judge he understands the penalty he faces if convicted.
Rapoport is due in court again in August.