I created a design in Inkscape and I was having an issue with the design converting to PDF. The problem is whenever I export it to PDF, the blurred shadow disappears in the PDF file. I need this solved ASAP because I need it to send it for print. I hope you understand.
Inkscape's effects can suffer when you make a PDF. That depends on used PDF engine and settings. The same problem has occurred also with blending modes:
As a first aid try to insert the shadow as separate object. Rasterize it. Edit > Make Bitmap Copy generates a rasterized copy. Set the rasterizing resolution high enough in the preferences.